IMPORTANT (for Python users): Python environment updated (34 software)

Summary: this is software update that involves Astropy and its
dependencies. In case you are using any of those, it is recommended to
reproduce the analysis of your project to make sure that the calls to the
various packages have not changed. If you are not using Astropy or its
dependencies, this commit will not affect your analysis.

Until this commit, Astropy and the whole Python environment of its
prerequisites were last updated more than 2 years go. So after the update
of the Basic and some high-level (Gnuastro dependencies) software, it was
necessary to update Astropy and its dependencies (for those who use it).

With this commit, the software listed in the last item below have been
updated as well as the following minor technical fixes:

  - Support bug 110738 (https://savannah.nongnu.org/support/?110738): when
    the build directory had the same base-name as the source directory (for
    exapmle '/PATH/proj' and /PATH/proj-build'), Maneage would complain and
    not continue.

  - The Python software are now built using the wheels system with
    'gpep517' (https://pypi.org/project/gpep517). Python packages that are
    not required by astropy/matplotlib/scipy have mostly not been updated,
    but updating their dependencies and adding the build method as
    'GPEP517' should be straightforward.

  - Updated software (dependencies of Astropy). Those with 'N/A' in their
    previous version string weren't in Maneage prior to this commit.

    High-level software (not written in Python):

       boost                   1.77.0          1.87.0
       ninja build system      n/a             1.12.1
       openblas                0.3.21          0.3.29

    Python packages:

       python                  3.10.6          3.13.2
       astropy                 5.1             7.0.1
       astropy-iers-data       n/a             0.2025.2.24.0.34.4
       contourpy               n/a             1.3.1
       cppy                    n/a             1.3.1
       cycler                  0.11.0          0.12.1
       cython                  0.29.24         3.0.12
       extension-helpers       0.1             1.2.0
       features                n/a             0.5.12
       flit-core               n/a             3.11.0
       fonttools               n/a             4.56.0
       gpep517                 n/a             16
       kiwisolver              1.0.1           1.4.8
       matplotlib              3.3.0           3.10.0
       meson                   n/a             1.7.0
       meson-python            n/a             0.17.1
       numpy                   1.21.3          2.2.3
       packaging               21.3            24.2
       pillow                  8.4.0           11.1.0
       pybind11                2.5.0           2.13.6
       pyerfa-version          2.0.0.1         2.0.1.5
       pyproject-metadata      n/a             0.9.0
       pyparsing               3.0.4           3.2.1
       python-dateutil         2.8.0           2.9.0.post0
       python-installer        n/a             0.7.0
       pyyaml                  5.1             6.0.2
       setuptools              58.3.0          75.8.0
       setuptools_scm          3.3.3           8.2.0
       scipy                   1.7.3           1.15.2
       six                     1.16.0          1.17.0
       wheel                   0.37.0          0.45.1

1 files changed, 424 insertions, 119 deletions

diff --git a/reproduce/software/make/python.mk b/reproduce/software/make/python.mk
index 43e2e77..871bad7 100644
--- a/reproduce/software/make/python.mk
+++ b/reproduce/software/make/python.mk
@@ -51,6 +51,8 @@ export MPI_PYTHON3_SITEARCH   :=
 # Python-specific installation directories.
 python-major-version = $(shell echo $(python-version) | awk 'BEGIN{FS="."} \
 	                            {printf "%d.%d\n", $$1, $$2}')
+# This is for 'installer' (the python installer) itself:
+ilibpymajorversion = $(idir)/lib/python$(python-major-version)
 
 
 
@@ -97,7 +99,7 @@ $(ibidir)/python-$(python-version): $(ibidir)/libffi-$(libffi-version)
 #	Unpack the tarball (see below for the necessary modification).
 	cd $(ddir)
 	unpackdir=python-$(python-version)
-	tar -xf $(tdir)/$$unpackdir.tar.lz
+	tar -xf $(tdir)/$$tarball
 	cd $$unpackdir
 	$(shsrcdir)/prep-source.sh $(ibdir)
 
@@ -143,39 +145,138 @@ $(ibidir)/python-$(python-version): $(ibidir)/libffi-$(libffi-version)
 
 
 
-# Non-PiP Python module installation
+# Non-pip Python module installation
 # ----------------------------------
 #
-# To build Python packages with direct access to a 'setup.py' (if no direct
-# access to 'setup.py' is needed, pip can be used). Note that the
-# software's packaged source code is the first prerequisite that is in the
-# 'tdir' directory.
+# Build strategy for python modules as of February 2025, for python 3.13.2.
+
+# This strategy is mostly based on recommendations by E Schwartz
+# (ztrawhcse) on #python (Libera Chat), in October 2022 and February
+# 2025. Some discussions are on documented in Savannah tasks [1][2]. The
+# build strategy for 'python-installer' is inspired by the gentoo script
+# 'python_domodule' [3].
+
+# Bootstrap-step: 'gpep517' [4], motivated by PEP 517 [5], together with
+# 'python-installer' (module called 'installer') are built without
+# dependences on other python packages apart from python itself.  The build
+# rules for these two packages do python byte compilation and copy the .py
+# and .pyc files into the python install directory. These two packages are
+# considered to be 'frontends'.
+
+# Once these two frontends are available, other packages that do building
+# tasks, including both backends and alternative frontends or a mix of
+# these (in particular: setuptools, meson [6]/ninja-build [7] , flit-core,
+# and meson-python), can be built with the 'python-installer' and
+# 'gpep517'.  The aims of the various build tools are diverse, include
+# ecosystem resilience, reproducibility, build speed and convenience in
+# building bigger packages such as numpy, scipy and astropy.
+
+# The python.mk script now includes only three methods: the boot
+# build methods of 'python-installer' and 'gpep517'; and the gpep517
+# frontend. No method is provided for using 'python-installer' directly;
+# it is invoked indirectly by source files of many packages, which
+# also give metadata describing information for build methods.
+
+# Why not pip? We do not build any python packages with 'pip' because we
+# want to have a fully documented pipeline of (i) the original upstream
+# locations of tarballs, (ii) the tarballs' checksums, and (iii) the exact
+# sequence of build commands.
+
+# For an alternative viewpoint on a python build strategy, see [8].
+
+# Prerequisite for the pybuild script here: the package's source code
+# (tarball) must already be located in the directory 'tdir'.
 #
-# Arguments of this function are the numbers
+# Arguments:
 #   1) Unpack command
 #   2) Unpacked directory name after unpacking the tarball
 #   3) site.cfg file (optional).
-#   4) Official software name (for paper).
+#   4) Official software name (for paper.tex).
+#   5) Obligatory parameter: build method (see below):
+#      BOOT_INSTALLER - only for 'python-installer'
+#      BOOT_GPEP517 - only for 'gpep517'
+#      GPEP517 - for any other python package
 #
 # Hooks:
 #   pyhook_before: optional steps before running 'python setup.py build'
 #   pyhook_after: optional steps after running 'python setup.py install'
-pybuild = cd $(ddir); rm -rf $(2); \
+
+# [1] https://savannah.nongnu.org/task/?16268
+# [2] https://savannah.nongnu.org/task/?16625
+# [3] https://gitweb.gentoo.org/repo/gentoo.git/tree/eclass/python-utils-r1.eclass#n646
+# [4] https://pypi.org/project/gpep517
+# [5] https://peps.python.org/pep-0517
+# [6] https://mesonbuild.com
+# [7] https://ninja-build.org
+# [8] https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html
+
+
+pybuild = cd $(ddir); \
+	packagedir=$(strip $(2)); \
+	if (printf "$$packagedir" | grep "[a-z][a-z]"); then rm -rf $$packagedir; fi; \
+	printf "\nStarting to install python package with maneage pybuild rule: $(4)\n ..."; \
 	if ! $(1) $(tdir)/$$tarball; then \
 	  echo; echo "Tar error"; exit 1; \
 	fi; \
-	cd $(2); \
+	cd $$packagedir; \
 	if [ "x$(strip $(3))" != x ]; then \
 	  sed -e 's|@LIBDIR[@]|'"$(ildir)"'|' \
 	      -e 's|@INCDIR[@]|'"$(idir)/include"'|' \
 	      $(3) > site.cfg; \
 	fi; \
 	if type pyhook_before &>/dev/null; then pyhook_before; fi; \
-	python setup.py build; \
-	python setup.py install; \
+	printf "pybuild option5 = __ %s __\n" "$(strip $(5))"; \
+	if [ "x$(strip $(5))" = xBOOT_INSTALLER ]; then \
+	   chmod 0644 src/installer/*.py; \
+	   mkdir -p $(ilibpymajorversion)/installer; \
+	   mkdir -p $(ilibpymajorversion)/installer/__pycache__ ; \
+	   mkdir -p $(ilibpymajorversion)/installer/_scripts; \
+	   mkdir -p $(ilibpymajorversion)/installer/_scripts/__pycache__ ; \
+	   cp -pv src/installer/*.py $(ilibpymajorversion)/installer/; \
+	   cp -pv src/installer/_scripts/__init__.py $(ilibpymajorversion)/installer/_scripts/; \
+	   cd src/installer/; \
+	   python -m compileall -o 1 -o 2 -l -f \
+	       -d $(ilibpymajorversion)/installer/ .; \
+	   chmod 0644 __pycache__/*.pyc; \
+	   cp -pv __pycache__/*.pyc \
+	        $(ilibpymajorversion)/installer/__pycache__; \
+	   cd -; \
+	   cd src/installer/_scripts/; \
+	   python -m compileall -o 1 -o 2 -l -f \
+	       -d $(ilibpymajorversion)/installer/_scripts/ __init__.py; \
+	   chmod 0644 __pycache__/*.pyc; \
+	   cp -pv __pycache__/*.pyc \
+	        $(ilibpymajorversion)/installer/_scripts/__pycache__; \
+	   cd -; \
+	elif [ "x$(strip $(5))" = xBOOT_GPEP517 ]; then \
+	   chmod 0644 gpep517/*.py; \
+	   mkdir -p $(ilibpymajorversion)/gpep517; \
+	   mkdir -p $(ilibpymajorversion)/gpep517/__pycache__ ; \
+	   cp -pv gpep517/*.py $(ilibpymajorversion)/gpep517/; \
+	   cd gpep517/; \
+	   python -m compileall -o 1 -o 2 -l -f \
+	       -d $(ilibpymajorversion)/gpep517/ .; \
+	   chmod 0644 __pycache__/*.pyc; \
+	   cp -pv __pycache__/*.pyc \
+	        $(ilibpymajorversion)/gpep517/__pycache__; \
+	   cd -; \
+	elif [ "x$(strip $(5))" = xGPEP517 ]; then \
+	   printf "\n\n\n=== python build method: gpep517 ====== "; pwd; \
+	   printf "...............\n\n\n"; \
+	   python -m gpep517 install-from-source \
+	      --prefix "" \
+	      --destdir $(idir) \
+	      --optimize all; \
+	else \
+	   printf "Error: Unknown pybuild method for $$packagedir: __ $(strip $(5)) __\n"; \
+	   printf "The pybuild 5th parameter should very likely be set "; \
+	   printf "to GPEP517 after checking the build rule and "; \
+	   printf "upgrading if needed.\n"; \
+	   exit 1; \
+	fi; \
 	if type pyhook_after &>/dev/null; then pyhook_after; fi; \
 	cd ..; \
-	rm -rf $(2); \
+	if (printf "$$packagedir" | grep "[a-z][a-z]"); then rm -fr $$packagedir; fi; \
 	echo "$(4)" > $@
 
 
@@ -184,9 +285,11 @@ pybuild = cd $(ddir); rm -rf $(2); \
 
 # Python modules
 # ---------------
-#
+
+
 # All the necessary Python modules go here.
-$(ipydir)/asn1crypto-$(asn1crypto-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/asn1crypto-$(asn1crypto-version): \
+                     $(ipydir)/setuptools-$(setuptools-version)
 	tarball=asn1crypto-$(asn1crypto-version).tar.gz
 	$(call import-source, $(asn1crypto-url), $(asn1crypto-checksum))
 	$(call pybuild, tar -xf, asn1crypto-$(asn1crypto-version), , \
@@ -207,25 +310,58 @@ $(ipydir)/astroquery-$(astroquery-version): \
 	$(call pybuild, tar -xf, astroquery-$(astroquery-version), , \
 	                Astroquery $(astroquery-version))
 
+# Astropy: points to consider about dependencies:
+#
 # The optional dependency 'h5py' that is necessary for writting tables in
 # HDF5 format has been removed from Astropy because on macOS it cannot be
 # installed.
+#
+# 2022-or-older dependencies:
+#                  $(ibidir)/expat-$(expat-version) \
+#                  $(ipydir)/jinja2-$(jinja2-version) \
+#                  $(ipydir)/html5lib-$(html5lib-version) \
+#                  $(ipydir)/beautifulsoup4-$(beautifulsoup4-version) \
+#
+# While the astropy pyproject.toml file says that the astropy build depends
+# on numpy, not scipy, and does not depend on matplotlib; the
+# runtime is recommended to depend on both scipy and matplotlib.
+# In practice, users of astropy will generally expect scipy and matplotlib
+# to be available at runtime, so we set these as prerequisites.
 $(ipydir)/astropy-$(astropy-version): \
-                  $(ibidir)/expat-$(expat-version) \
                   $(ipydir)/scipy-$(scipy-version) \
-                  $(ipydir)/numpy-$(numpy-version) \
-                  $(ipydir)/pyyaml-$(pyyaml-version) \
-                  $(ipydir)/jinja2-$(jinja2-version) \
                   $(ipydir)/pyerfa-$(pyerfa-version) \
-                  $(ipydir)/html5lib-$(html5lib-version) \
-                  $(ipydir)/beautifulsoup4-$(beautifulsoup4-version) \
+                  $(ipydir)/pyyaml-$(pyyaml-version) \
+                  $(ipydir)/matplotlib-$(matplotlib-version) \
+                  $(ipydir)/astropy-iers-data-$(astropy-iers-data-version) \
                   $(ipydir)/extension-helpers-$(extension-helpers-version)
+
+#	Tarball and its preparation.
 	tarball=astropy-$(astropy-version).tar.lz
 	$(call import-source, $(astropy-url), $(astropy-checksum))
-	$(call pybuild, tar -xf, astropy-$(astropy-version))
-	cp $(dtexdir)/astropy.tex $(ictdir)/
+
+#	Conservatively purge old version (but not astropy_iers,
+#	astropy-iers):
+	rm -fvr $(idir)/lib/python*/site-packages/astropy/
+	rm -fvr $(idir)/lib/python*/site-packages/astropy-[0-9]*-info/
+	rm -fv $(idir)/bin/fits{diff,check,header,info,2bitmap}
+	rm -fv $(idir)/bin/{samp_hub,showtable,volint,wcslint}
+
+#	Do the basic build.
+	$(call pybuild, tar -xf, astropy-$(astropy-version),,, \
+	                GPEP517)
+	cp -pv $(dtexdir)/astropy.tex $(ictdir)/
 	echo "Astropy $(astropy-version) \citep{astropy2013,astropy2018}" > $@
 
+$(ipydir)/astropy-iers-data-$(astropy-iers-data-version): \
+                            $(ipydir)/setuptools-$(setuptools-version)
+	tarball=astropy-iers-data-$(astropy-iers-data-version).tar.lz
+	$(call import-source, $(astropy-iers-data-url), \
+	         $(astropy-iers-data-checksum))
+	$(call pybuild, tar -xf, \
+	                astropy-iers-data-$(astropy-iers-data-version),,, \
+	                GPEP517)
+	echo "Astropy-Iers-Data $(astropy-iers-data-version)" > $@
+
 $(ipydir)/beautifulsoup4-$(beautifulsoup4-version): \
                          $(ipydir)/soupsieve-$(soupsieve-version)
 	tarball=beautifulsoup4-$(beautifulsoup4-version).tar.lz
@@ -233,13 +369,17 @@ $(ipydir)/beautifulsoup4-$(beautifulsoup4-version): \
 	$(call pybuild, tar -xf, beautifulsoup4-$(beautifulsoup4-version), , \
 	                BeautifulSoup $(beautifulsoup4-version))
 
-$(ipydir)/beniget-$(beniget-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/beniget-$(beniget-version): \
+                  $(ipydir)/gpep517-$(gpep517-version) \
+                  $(ipydir)/python-installer-$(python-installer-version)
 	tarball=beniget-$(beniget-version).tar.lz
 	$(call import-source, $(beniget-url), $(beniget-checksum))
 	$(call pybuild, tar -xf, beniget-$(beniget-version), , \
 	                Beniget $(beniget-version))
 
-$(ipydir)/certifi-$(certifi-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/certifi-$(certifi-version): \
+                  $(ipydir)/gpep517-$(gpep517-version) \
+                  $(ipydir)/python-installer-$(python-installer-version)
 	tarball=certifi-$(certifi-version).tar.gz
 	$(call import-source, $(certifi-url), $(certifi-checksum))
 	$(call pybuild, tar -xf, certifi-$(certifi-version), , \
@@ -252,12 +392,23 @@ $(ipydir)/cffi-$(cffi-version): \
 	$(call import-source, $(cffi-url), $(cffi-checksum))
 	$(call pybuild, tar -xf, cffi-$(cffi-version), ,cffi $(cffi-version))
 
-$(ipydir)/chardet-$(chardet-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/chardet-$(chardet-version): \
+                  $(ipydir)/gpep517-$(gpep517-version) \
+                  $(ipydir)/python-installer-$(python-installer-version)
 	tarball=chardet-$(chardet-version).tar.gz
 	$(call import-source, $(chardet-url), $(chardet-checksum))
 	$(call pybuild, tar -xf, chardet-$(chardet-version), , \
 	                Chardet $(chardet-version))
 
+$(ipydir)/contourpy-$(contourpy-version): \
+                     $(ipydir)/pybind11-$(pybind11-version) \
+                     $(ipydir)/meson-python-$(meson-python-version)
+	tarball=contourpy-$(contourpy-version).tar.lz
+	$(call import-source, $(contourpy-url), $(contourpy-checksum))
+	$(call pybuild, tar -xf, contourpy-$(contourpy-version), , \
+	                Contourpy $(contourpy-version), GPEP517)
+	echo "Contourpy $(contourpy-version)" > $@
+
 $(ipydir)/corner-$(corner-version): $(ipydir)/matplotlib-$(matplotlib-version)
 	tarball=corner-$(corner-version).tar.gz
 	$(call import-source, $(corner-url), $(corner-checksum))
@@ -266,6 +417,13 @@ $(ipydir)/corner-$(corner-version): $(ipydir)/matplotlib-$(matplotlib-version)
 	cp $(dtexdir)/corner.tex $(ictdir)/
 	echo "Corner $(corner-version) \citep{corner}" > $@
 
+$(ipydir)/cppy-$(cppy-version): \
+               $(ipydir)/setuptools-scm-$(setuptools-scm-version)
+	tarball=cppy-$(cppy-version).tar.lz
+	$(call import-source, $(cppy-url), $(cppy-checksum))
+	$(call pybuild, tar -xf, cppy-$(cppy-version), , \
+	                Cppy $(cppy-version), GPEP517)
+
 $(ipydir)/cryptography-$(cryptography-version): \
                        $(ipydir)/cffi-$(cffi-version) \
                        $(ipydir)/asn1crypto-$(asn1crypto-version) \
@@ -279,13 +437,17 @@ $(ipydir)/cycler-$(cycler-version): $(ipydir)/six-$(six-version)
 	tarball=cycler-$(cycler-version).tar.lz
 	$(call import-source, $(cycler-url), $(cycler-checksum))
 	$(call pybuild, tar -xf, cycler-$(cycler-version), , \
-	                Cycler $(cycler-version))
+	                Cycler $(cycler-version), GPEP517)
+	echo "Cycler $(cycler-version)" > $@
 
-$(ipydir)/cython-$(cython-version): $(ipydir)/setuptools-$(setuptools-version)
-	tarball=Cython-$(cython-version).tar.lz
+$(ipydir)/cython-$(cython-version): \
+                 $(ipydir)/python-installer-$(python-installer-version) \
+                 $(ipydir)/gpep517-$(gpep517-version) \
+                 $(ipydir)/setuptools-$(setuptools-version)
+	tarball=cython-$(cython-version).tar.lz
 	$(call import-source, $(cython-url), $(cython-checksum))
-	$(call pybuild, tar -xf, Cython-$(cython-version))
-	cp $(dtexdir)/cython.tex $(ictdir)/
+	$(call pybuild, tar -xf, cython-$(cython-version),,, GPEP517)
+	cp -pv $(dtexdir)/cython.tex $(ictdir)/
 	echo "Cython $(cython-version) \citep{cython2011}" > $@
 
 $(ipydir)/esutil-$(esutil-version): $(ipydir)/numpy-$(numpy-version)
@@ -306,26 +468,28 @@ $(ipydir)/eigency-$(eigency-version): \
 
 $(ipydir)/emcee-$(emcee-version): \
                 $(ipydir)/numpy-$(numpy-version) \
-                $(ipydir)/setuptools_scm-$(setuptools_scm-version)
+                $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=emcee-$(emcee-version).tar.gz
 	$(call import-source, $(emcee-url), $(emcee-checksum))
 	$(call pybuild, tar -xf, emcee-$(emcee-version), , \
 	                emcee $(emcee-version))
 
 $(ipydir)/entrypoints-$(entrypoints-version): \
-                      $(ipydir)/setuptools-$(setuptools-version)
+                      $(ipydir)/gpep517-$(gpep517-version) \
+                      $(ipydir)/python-installer-$(python-installer-version)
 	tarball=entrypoints-$(entrypoints-version).tar.gz
 	$(call import-source, $(entrypoints-url), $(entrypoints-checksum))
 	$(call pybuild, tar -xf, entrypoints-$(entrypoints-version), , \
 	                EntryPoints $(entrypoints-version))
 
 $(ipydir)/extension-helpers-$(extension-helpers-version): \
-                    $(ipydir)/setuptools-$(setuptools-version) \
-                    $(ipydir)/setuptools_scm-$(setuptools_scm-version)
+                    $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=extension-helpers-$(extension-helpers-version).tar.lz
-	$(call import-source, $(extension-helpers-url), $(extension-helpers-checksum))
-	$(call pybuild, tar -xf, extension-helpers-$(extension-helpers-version), , \
-	                Extension-Helpers $(extension-helpers-version))
+	$(call import-source, $(extension-helpers-url), \
+	      $(extension-helpers-checksum))
+	$(call pybuild, tar -xf, \
+	                extension-helpers-$(extension-helpers-version),, \
+	                Extension-Helpers $(extension-helpers-version), GPEP517)
 
 $(ipydir)/flake8-$(flake8-version): \
                  $(ipydir)/pyflakes-$(pyflakes-version) \
@@ -335,12 +499,41 @@ $(ipydir)/flake8-$(flake8-version): \
 	$(call pybuild, tar -xf, flake8-$(flake8-version), , \
 	                Flake8 $(flake8-version))
 
-$(ipydir)/future-$(future-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/flit-core-$(flit-core-version): \
+                     $(ipydir)/gpep517-$(gpep517-version) \
+                     $(ipydir)/python-installer-$(python-installer-version)
+	tarball=flit-core-$(flit-core-version).tar.lz
+	$(call import-source, $(flit-core-url), $(flit-core-checksum))
+	$(call pybuild, tar -xf, flit-core-$(flit-core-version), , \
+	                Flit-core $(flit-core-version), GPEP517)
+
+# Although cython is not an obligatory prerequisite of fonttools, we force
+# it as a prerequisite for reproducibility; otherwise build parallelism may
+# lead to some builds with and some builds without cython, depending on how
+# many cpus the host machine has.
+$(ipydir)/fonttools-$(fonttools-version): \
+                     $(ipydir)/cython-$(cython-version) \
+                     $(ipydir)/setuptools-$(setuptools-version)
+	tarball=fonttools-$(fonttools-version).tar.lz
+	$(call import-source, $(fonttools-url), $(fonttools-checksum))
+	$(call pybuild, tar -xf, fonttools-$(fonttools-version), , \
+	                fonttools $(fonttools-version), GPEP517)
+
+$(ipydir)/future-$(future-version): \
+                 $(ipydir)/gpep517-$(gpep517-version) \
+                 $(ipydir)/python-installer-$(python-installer-version)
 	tarball=future-$(future-version).tar.gz
 	$(call import-source, $(future-url), $(future-checksum))
 	$(call pybuild, tar -xf, future-$(future-version), , \
 	                Future $(future-version))
 
+$(ipydir)/cycler-$(cycler-version): $(ipydir)/six-$(six-version)
+	tarball=cycler-$(cycler-version).tar.lz
+	$(call import-source, $(cycler-url), $(cycler-checksum))
+	$(call pybuild, tar -xf, cycler-$(cycler-version), , \
+	                Cycler $(cycler-version), GPEP517)
+	echo "Cycler $(cycler-version)" > $@
+
 $(ipydir)/galsim-$(galsim-version): \
                  $(ipydir)/future-$(future-version) \
                  $(ipydir)/astropy-$(astropy-version) \
@@ -353,12 +546,25 @@ $(ipydir)/galsim-$(galsim-version): \
 	cp $(dtexdir)/galsim.tex $(ictdir)/
 	echo "Galsim $(galsim-version) \citep{galsim}" > $@
 
-$(ipydir)/gast-$(gast-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/gast-$(gast-version): \
+               $(ipydir)/gpep517-$(gpep517-version) \
+               $(ipydir)/python-installer-$(python-installer-version)
 	tarball=gast-$(gast-version).tar.lz
 	$(call import-source, $(gast-url), $(gast-checksum))
 	$(call pybuild, tar -xf, gast-$(gast-version), , \
 	                Gast $(gast-version))
 
+$(ipydir)/gpep517-$(gpep517-version): \
+                     $(ibidir)/python-$(python-version)
+	tarball=gpep517-$(gpep517-version).tar.lz
+	$(call import-source, $(gpep517-url), $(gpep517-checksum))
+	$(call pybuild, tar -xf, \
+	                gpep517-$(gpep517-version), \
+	                , \
+	                gpep517 $(gpep517-version), \
+	                BOOT_GPEP517)
+	echo "gpep517 $(gpep517-version)" > $@
+
 $(ipydir)/h5py-$(h5py-version): \
                $(ipydir)/six-$(six-version) \
                $(ibidir)/hdf5-$(hdf5-version) \
@@ -391,13 +597,17 @@ $(ipydir)/html5lib-$(html5lib-version): \
 	$(call pybuild, tar -xf, html5lib-$(html5lib-version), , \
 	                HTML5lib $(html5lib-version))
 
-$(ipydir)/idna-$(idna-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/idna-$(idna-version): \
+               $(ipydir)/gpep517-$(gpep517-version) \
+               $(ipydir)/python-installer-$(python-installer-version)
 	tarball=idna-$(idna-version).tar.gz
 	$(call import-source, $(idna-url), $(idna-checksum))
 	$(call pybuild, tar -xf, idna-$(idna-version), , \
 	       idna $(idna-version))
 
-$(ipydir)/jeepney-$(jeepney-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/jeepney-$(jeepney-version): \
+                     $(ipydir)/gpep517-$(gpep517-version) \
+                     $(ipydir)/python-installer-$(python-installer-version)
 	tarball=jeepney-$(jeepney-version).tar.gz
 	$(call import-source, $(jeepney-url), $(jeepney-checksum))
 	$(call pybuild, tar -xf, jeepney-$(jeepney-version), , \
@@ -412,17 +622,21 @@ $(ipydir)/jinja2-$(jinja2-version): $(ipydir)/markupsafe-$(markupsafe-version)
 $(ipydir)/keyring-$(keyring-version): \
                   $(ipydir)/entrypoints-$(entrypoints-version) \
                   $(ipydir)/secretstorage-$(secretstorage-version) \
-                  $(ipydir)/setuptools_scm-$(setuptools_scm-version)
+                  $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=keyring-$(keyring-version).tar.gz
 	$(call import-source, $(keyring-url), $(keyring-checksum))
 	$(call pybuild, tar -xf, keyring-$(keyring-version), , \
 	                Keyring $(keyring-version))
 
-$(ipydir)/kiwisolver-$(kiwisolver-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/kiwisolver-$(kiwisolver-version): \
+                     $(ipydir)/cppy-$(cppy-version) \
+                     $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=kiwisolver-$(kiwisolver-version).tar.lz
 	$(call import-source, $(kiwisolver-url), $(kiwisolver-checksum))
 	$(call pybuild, tar -xf, kiwisolver-$(kiwisolver-version), , \
-	                Kiwisolver $(kiwisolver-version))
+	                Kiwisolver $(kiwisolver-version), GPEP517)
+	cp -pv $(dtexdir)/kiwisolver.tex $(ictdir)/
+	echo "Kiwisolver $(kiwisolver-version) \citep{cassowary2001}" > $@
 
 $(ipydir)/lmfit-$(lmfit-version): \
                 $(ipydir)/six-$(six-version) \
@@ -447,7 +661,8 @@ $(ipydir)/lsstdesccoord-$(lsstdesccoord-version): \
 	                LSSTDESC.Coord $(lsstdesccoord-version))
 
 $(ipydir)/markupsafe-$(markupsafe-version): \
-                     $(ipydir)/setuptools-$(setuptools-version)
+                     $(ipydir)/gpep517-$(gpep517-version) \
+                     $(ipydir)/python-installer-$(python-installer-version)
 	tarball=markupsafe-$(markupsafe-version).tar.lz
 	$(call import-source, $(markupsafe-url), $(markupsafe-checksum))
 	$(call pybuild, tar -xf, markupsafe-$(markupsafe-version), , \
@@ -458,11 +673,9 @@ $(ipydir)/matplotlib-$(matplotlib-version): \
                      $(ipydir)/numpy-$(numpy-version) \
                      $(ipydir)/cycler-$(cycler-version) \
                      $(ipydir)/pillow-$(pillow-version) \
-                     $(ibidir)/freetype-$(freetype-version) \
-                     $(ipydir)/pyparsing-$(pyparsing-version) \
+                     $(ipydir)/fonttools-$(fonttools-version) \
+                     $(ipydir)/contourpy-$(contourpy-version) \
                      $(ipydir)/kiwisolver-$(kiwisolver-version) \
-                     $(ibidir)/ghostscript-$(ghostscript-version) \
-                     $(ibidir)/imagemagick-$(imagemagick-version) \
                      $(ipydir)/python-dateutil-$(python-dateutil-version)
 
 #	Prepare the source.
@@ -475,40 +688,63 @@ $(ipydir)/matplotlib-$(matplotlib-version): \
 	  export CC=clang
 	  export CXX=clang++
 	fi
-	$(call pybuild, tar -xf, matplotlib-$(matplotlib-version))
+	$(call pybuild, tar -xf, matplotlib-$(matplotlib-version),,, GPEP517)
 	cp $(dtexdir)/matplotlib.tex $(ictdir)/
 	echo "Matplotlib $(matplotlib-version) \citep{matplotlib2007}" > $@
 
+$(ipydir)/meson-$(meson-version): \
+                         $(ibidir)/ninjabuild-$(ninjabuild-version) \
+                         $(ipydir)/setuptools-$(setuptools-version)
+	tarball=meson-$(meson-version).tar.lz
+	$(call import-source, $(meson-url), $(meson-checksum))
+	$(call pybuild, tar -xf, meson-$(meson-version), , \
+	                Meson $(meson-version), GPEP517)
+	echo "Meson $(meson-version)" > $@
+
+# The 'meson-python' package may be helpful or requred for some packages.
+$(ipydir)/meson-python-$(meson-python-version): \
+                         $(ipydir)/meson-$(meson-version) \
+                         $(ipydir)/packaging-$(packaging-version) \
+                         $(ipydir)/pyproject-metadata-$(pyproject-metadata-version)
+	tarball=meson-python-$(meson-python-version).tar.lz
+	$(call import-source, $(meson-python-url), $(meson-python-checksum))
+	$(call pybuild, tar -xf, meson-python-$(meson-python-version), , \
+	                Meson-python $(meson-python-version), GPEP517)
+	echo "Meson-Python $(meson-python-version)" > $@
+
 $(ipydir)/mpi4py-$(mpi4py-version): \
+                 $(ipydir)/gpep517-$(gpep517-version) \
                  $(ibidir)/openmpi-$(openmpi-version) \
-                 $(ipydir)/setuptools-$(setuptools-version)
+                 $(ipydir)/python-installer-$(python-installer-version)
 	tarball=mpi4py-$(mpi4py-version).tar.lz
 	$(call import-source, $(mpi4py-url), $(mpi4py-checksum))
 	$(call pybuild, tar -xf, mpi4py-$(mpi4py-version))
 	cp $(dtexdir)/mpi4py.tex $(ictdir)/
 	echo "mpi4py $(mpi4py-version) \citep{mpi4py2011}" > $@
 
-$(ipydir)/mpmath-$(mpmath-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/mpmath-$(mpmath-version): \
+                     $(ipydir)/gpep517-$(gpep517-version) \
+                     $(ipydir)/python-installer-$(python-installer-version)
 	tarball=mpmath-$(mpmath-version).tar.gz
 	$(call import-source, $(mpmath-url), $(mpmath-checksum))
 	$(call pybuild, tar -xf, mpmath-$(mpmath-version), , \
 	                mpmath $(mpmath-version))
 
+# Until 2025-02-22: we had 'export CFLAGS="--std=c99 $$CFLAGS"' before
+# calling pybuild; but that doesn't seem to be necessary.
 $(ipydir)/numpy-$(numpy-version): \
                 $(ipydir)/cython-$(cython-version) \
                 $(ibidir)/openblas-$(openblas-version) \
-                $(ipydir)/setuptools-$(setuptools-version)
+                $(ipydir)/pybind11-$(pybind11-version) \
+                $(ipydir)/meson-python-$(meson-python-version)
 	tarball=numpy-$(numpy-version).tar.lz
 	$(call import-source, $(numpy-url), $(numpy-checksum))
 	if [ x$(on_mac_os) = xyes ]; then
 	  export LDFLAGS="$(LDFLAGS) -undefined dynamic_lookup -bundle"
-	else
-	  export LDFLAGS="$(LDFLAGS) -shared"
 	fi
-	export CFLAGS="--std=c99 $$CFLAGS"
 	conf="$$(pwd)/reproduce/software/config/numpy-scipy.cfg"
 	$(call pybuild, tar -xf, numpy-$(numpy-version),$$conf, \
-	                Numpy $(numpy-version))
+	                Numpy $(numpy-version), GPEP517)
 	cp $(dtexdir)/numpy.tex $(ictdir)/
 	echo "Numpy $(numpy-version) \citep{numpy2020}" > $@
 
@@ -517,9 +753,11 @@ $(ipydir)/packaging-$(packaging-version): \
 	tarball=packaging-$(packaging-version).tar.lz
 	$(call import-source, $(packaging-url), $(packaging-checksum))
 	$(call pybuild, tar -xf, packaging-$(packaging-version), , \
-	                Packaging $(packaging-version))
+	                Packaging $(packaging-version), GPEP517)
 
-$(ipydir)/pexpect-$(pexpect-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/pexpect-$(pexpect-version): \
+                  $(ipydir)/gpep517-$(gpep517-version) \
+                  $(ipydir)/python-installer-$(python-installer-version)
 	tarball=pexpect-$(pexpect-version).tar.gz
 	$(call import-source, $(pexpect-url), $(pexpect-checksum))
 	$(call pybuild, tar -xf, pexpect-$(pexpect-version), , \
@@ -527,25 +765,32 @@ $(ipydir)/pexpect-$(pexpect-version): $(ipydir)/setuptools-$(setuptools-version)
 
 $(ipydir)/pillow-$(pillow-version): $(ibidir)/libjpeg-$(libjpeg-version) \
                  $(ipydir)/setuptools-$(setuptools-version)
-	tarball=Pillow-$(pillow-version).tar.lz
+	tarball=pillow-$(pillow-version).tar.lz
 	$(call import-source, $(pillow-url), $(pillow-checksum))
-	$(call pybuild, tar -xf, Pillow-$(pillow-version), , \
-	                Pillow $(pillow-version))
-
-$(ipydir)/pip-$(pip-version): $(ipydir)/setuptools-$(setuptools-version)
-	tarball=pip-$(pip-version).tar.gz
-	$(call import-source, $(pip-url), $(pip-checksum))
-	$(call pybuild, tar -xf, pip-$(pip-version), , \
-	                PiP $(pip-version))
-
-$(ipydir)/ply-$(ply-version): $(ipydir)/setuptools-$(setuptools-version)
+	$(call pybuild, tar -xf, pillow-$(pillow-version), , \
+	                Pillow $(pillow-version), GPEP517)
+
+# This should normally not be used, because it's a front-end that obstructs
+# reproducibility - source URL; checksum of the tarball; build rule.
+# $(ipydir)/pip-$(pip-version): \
+#                      $(ipydir)/python-installer-$(python-installer-version) \
+#                      $(ipydir)/wheel-$(wheel-version)
+# 	tarball=pip-$(pip-version).tar.gz
+# 	$(call import-source, $(pip-url), $(pip-checksum))
+# 	$(call pybuild, tar -xf, pip-$(pip-version), , \
+# 	                PiP $(pip-version))
+
+$(ipydir)/ply-$(ply-version): \
+              $(ipydir)/gpep517-$(gpep517-version) \
+              $(ipydir)/python-installer-$(python-installer-version)
 	tarball=ply-$(ply-version).tar.lz
 	$(call import-source, $(ply-url), $(ply-checksum))
 	$(call pybuild, tar -xf, ply-$(ply-version), , \
 	                ply $(ply-version))
 
 $(ipydir)/pycodestyle-$(pycodestyle-version): \
-                      $(ipydir)/setuptools-$(setuptools-version)
+                     $(ipydir)/gpep517-$(gpep517-version) \
+                     $(ipydir)/python-installer-$(python-installer-version)
 	tarball=pycodestyle-$(pycodestyle-version).tar.gz
 	$(call import-source, $(pycodestyle-url), $(pycodestyle-checksum))
 	$(call pybuild, tar -xf, pycodestyle-$(pycodestyle-version), , \
@@ -554,16 +799,21 @@ $(ipydir)/pycodestyle-$(pycodestyle-version): \
 $(ipydir)/pybind11-$(pybind11-version): \
                    $(ibidir)/eigen-$(eigen-version) \
                    $(ibidir)/boost-$(boost-version) \
-                   $(ipydir)/setuptools-$(setuptools-version)
-	tarball=pybind11-$(pybind11-version).tar.gz
+                   $(ipydir)/gpep517-$(gpep517-version) \
+                   $(ipydir)/python-installer-$(python-installer-version)
+	tarball=pybind11-$(pybind11-version).tar.lz
 	$(call import-source, $(pybind11-url), $(pybind11-checksum))
 	pyhook_after() {
-	  cp -r include/pybind11 $(iidir)/python$(python-major-version)m/
+	   cp -pvr pybind11/include/pybind11 \
+	        $(iidir)/python$(python-major-version)m/
 	}
 	$(call pybuild, tar -xf, pybind11-$(pybind11-version), , \
-	                pybind11 $(pybind11-version))
+	                pybind11 $(pybind11-version), GPEP517)
+	echo "Pybind11 $(pybind11-version)" > $@
 
-$(ipydir)/pycparser-$(pycparser-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/pycparser-$(pycparser-version): \
+                     $(ipydir)/gpep517-$(gpep517-version) \
+                     $(ipydir)/python-installer-$(python-installer-version)
 	tarball=pycparser-$(pycparser-version).tar.gz
 	$(call import-source, $(pycparser-url), $(pycparser-checksum))
 	$(call pybuild, tar -xf, pycparser-$(pycparser-version), , \
@@ -571,46 +821,68 @@ $(ipydir)/pycparser-$(pycparser-version): $(ipydir)/setuptools-$(setuptools-vers
 
 $(ipydir)/pyerfa-$(pyerfa-version): \
                  $(ipydir)/numpy-$(numpy-version) \
-                 $(ipydir)/packaging-$(packaging-version) \
-                 $(ipydir)/setuptools_scm-$(setuptools_scm-version)
+                 $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=pyerfa-$(pyerfa-version).tar.lz
 	$(call import-source, $(pyerfa-url), $(pyerfa-checksum))
 	$(call pybuild, tar -xf, pyerfa-$(pyerfa-version), , \
-	                PyERFA $(pyerfa-version))
+	                PyERFA $(pyerfa-version), GPEP517)
 
-$(ipydir)/pyflakes-$(pyflakes-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/pyflakes-$(pyflakes-version): \
+                $(ipydir)/gpep517-$(gpep517-version) \
+                $(ipydir)/python-installer-$(python-installer-version)
 	tarball=pyflakes-$(pyflakes-version).tar.gz
 	$(call import-source, $(pyflakes-url), $(pyflakes-checksum))
 	$(call pybuild, tar -xf, pyflakes-$(pyflakes-version), , \
 	                pyflakes $(pyflakes-version))
 
 $(ipydir)/pyparsing-$(pyparsing-version): \
-                    $(ipydir)/setuptools-$(setuptools-version)
+                    $(ipydir)/gpep517-$(gpep517-version) \
+                    $(ipydir)/flit-core-$(flit-core-version) \
+                    $(ipydir)/python-installer-$(python-installer-version)
 	tarball=pyparsing-$(pyparsing-version).tar.lz
 	$(call import-source, $(pyparsing-url), $(pyparsing-checksum))
 	$(call pybuild, tar -xf, pyparsing-$(pyparsing-version), , \
-	                PyParsing $(pyparsing-version))
+	                PyParsing $(pyparsing-version), GPEP517)
 
-$(ipydir)/pypkgconfig-$(pypkgconfig-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/pypkgconfig-$(pypkgconfig-version): \
+                      $(ipydir)/gpep517-$(gpep517-version) \
+                      $(ipydir)/python-installer-$(python-installer-version)
 	tarball=pkgconfig-$(pypkgconfig-version).tar.gz
 	$(call import-source, $(pypkgconfig-url), $(pypkgconfig-checksum))
 	$(call pybuild, tar -xf, pkgconfig-$(pypkgconfig-version), ,
 	                pkgconfig $(pypkgconfig-version))
 
+$(ipydir)/pyproject-metadata-$(pyproject-metadata-version): \
+                    $(ipydir)/gpep517-$(gpep517-version) \
+                    $(ipydir)/flit-core-$(flit-core-version) \
+                    $(ipydir)/python-installer-$(python-installer-version)
+	tarball=pyproject-metadata-$(pyproject-metadata-version).tar.lz
+	$(call import-source, $(pyproject-metadata-url), $(pyproject-metadata-checksum))
+	$(call pybuild, tar -xf, \
+	            pyproject-metadata-$(pyproject-metadata-version),,, GPEP517)
+
 $(ipydir)/python-dateutil-$(python-dateutil-version): \
-                          $(ipydir)/six-$(six-version) \
-                          $(ipydir)/setuptools_scm-$(setuptools_scm-version)
-	tarball=python-dateutil-$(python-dateutil-version).tar.gz
+                          $(ipydir)/setuptools-scm-$(setuptools-scm-version)
+	tarball=python-dateutil-$(python-dateutil-version).tar.lz
 	$(call import-source, $(python-dateutil-url), $(python-dateutil-checksum))
 	$(call pybuild, tar -xf, python-dateutil-$(python-dateutil-version), , \
-	                python-dateutil $(python-dateutil-version))
+	                python-dateutil $(python-dateutil-version), GPEP517)
+
+$(ipydir)/python-installer-$(python-installer-version): \
+                     $(ibidir)/python-$(python-version)
+	tarball=python-installer-$(python-installer-version).tar.lz
+	$(call import-source, $(python-installer-url), $(python-installer-checksum))
+	$(call pybuild, tar -xf, \
+	                python-installer-$(python-installer-version),,, \
+	                BOOT_INSTALLER)
+	echo "Python-installer $(python-installer-version)" > $@
 
 $(ipydir)/pythran-$(pythran-version): \
                   $(ipydir)/ply-$(ply-version) \
                   $(ipydir)/gast-$(gast-version) \
                   $(ibidir)/boost-$(boost-version) \
                   $(ipydir)/beniget-$(beniget-version) \
-                  $(ipydir)/setuptools_scm-$(setuptools_scm-version)
+                  $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=pythran-$(pythran-version).tar.lz
 	$(call import-source, $(pythran-url), $(pythran-checksum))
 	$(call pybuild, tar -xf, pythran-$(pythran-version), , \
@@ -619,25 +891,27 @@ $(ipydir)/pythran-$(pythran-version): \
 $(ipydir)/pyyaml-$(pyyaml-version): \
                  $(ibidir)/yaml-$(yaml-version) \
                  $(ipydir)/cython-$(cython-version)
-	tarball=pyyaml-$(pyyaml-version).tar.gz
+	tarball=pyyaml-$(pyyaml-version).tar.lz
 	$(call import-source, $(pyyaml-url), $(pyyaml-checksum))
-	$(call pybuild, tar -xf, PyYAML-$(pyyaml-version), , \
-	                PyYAML $(pyyaml-version))
+	$(call pybuild, tar -xf, pyyaml-$(pyyaml-version), , \
+	                PyYAML $(pyyaml-version), GPEP517)
 
 $(ipydir)/requests-$(requests-version): $(ipydir)/idna-$(idna-version) \
-                    $(ipydir)/numpy-$(numpy-version) \
-                    $(ipydir)/certifi-$(certifi-version) \
-                    $(ipydir)/chardet-$(chardet-version) \
-                    $(ipydir)/urllib3-$(urllib3-version)
+                   $(ipydir)/numpy-$(numpy-version) \
+                   $(ipydir)/certifi-$(certifi-version) \
+                   $(ipydir)/chardet-$(chardet-version) \
+                   $(ipydir)/urllib3-$(urllib3-version)
 	tarball=requests-$(requests-version).tar.gz
 	$(call import-source, $(requests-url), $(requests-checksum))
 	$(call pybuild, tar -xf, requests-$(requests-version), , \
 	                Requests $(requests-version))
 
 # 'pythran' is disabled in the build of Scipy because of complications it
-# caused on some systems. It is explicitly disabled using the environmental
-# variable. If for some reason it is needed, set the environment variable
-# to 1, and add it as a prerequisite of 'scipy'.
+# caused on some systems. We explicitly disable it using a preprocessor
+# directive. 'Pythran' can in principle speed up compilation of scientific
+# software [1][2].
+# [1] https://pythran.readthedocs.io/en/latest
+# [2] https://docs.scipy.org/doc/scipy-1.15.2/dev/roadmap-detailed.html
 $(ipydir)/scipy-$(scipy-version): \
                   $(ipydir)/numpy-$(numpy-version) \
                   $(ipydir)/pybind11-$(pybind11-version)
@@ -646,11 +920,28 @@ $(ipydir)/scipy-$(scipy-version): \
 	if [ x$(on_mac_os) = xyes ]; then
 	  export LDFLAGS="$(LDFLAGS) -undefined dynamic_lookup -bundle"
 	else
-	  export LDFLAGS="$(LDFLAGS) -shared"
+#	  Same question as for 'numpy': why '-shared'? This obstructs
+#	  the meson build.
+#	  export LDFLAGS="$(LDFLAGS) -shared"
+	  :
 	fi
-	export SCIPY_USE_PYTHRAN=0
 	conf="$$(pwd)/reproduce/software/config/numpy-scipy.cfg"
-	$(call pybuild, tar -xf, scipy-$(scipy-version),$$conf)
+
+#	Disable pythran: see
+#	https://docs.scipy.org/doc/scipy-1.15.2/dev/roadmap-detailed.html#use-of-pythran
+#	export SCIPY_USE_PYTHRAN=0 # deprecated(?)
+#	Option 1: Hack the source:
+	pyhook_before() {
+	   mv -iv meson.options meson.options.orig; \
+	   sed -e 's/\(use-pythran.*value: *\)true/\1false/' \
+	        meson.options.orig > meson.options
+	}
+
+#	Option 2: pass the string
+#	   --config-json='{"setup-args": "-Duse-pythran=false"}'
+#	to gpep517 with correct escaping of single and double quotes.
+#	Not tried as of 2025-02-25.
+	$(call pybuild, tar -xf, scipy-$(scipy-version),$$conf,, GPEP517)
 	cp $(dtexdir)/scipy.tex $(ictdir)/
 	echo "Scipy $(scipy-version) \citep{scipy2020}" > $@
 
@@ -663,21 +954,23 @@ $(ipydir)/secretstorage-$(secretstorage-version): \
 	                SecretStorage $(secretstorage-version))
 
 $(ipydir)/setuptools-$(setuptools-version): \
-                     $(ibidir)/python-$(python-version)
+                     $(ipydir)/gpep517-$(gpep517-version) \
+                     $(ipydir)/python-installer-$(python-installer-version)
 	tarball=setuptools-$(setuptools-version).tar.lz
 	$(call import-source, $(setuptools-url), $(setuptools-checksum))
 	$(call pybuild, tar -xf, setuptools-$(setuptools-version), , \
-	                Setuptools $(setuptools-version))
+	                Setuptools $(setuptools-version), GPEP517)
 
-$(ipydir)/setuptools_scm-$(setuptools_scm-version): \
+$(ipydir)/setuptools-scm-$(setuptools-scm-version): \
                          $(ipydir)/setuptools-$(setuptools-version)
-	tarball=setuptools_scm-$(setuptools_scm-version).tar.gz
-	$(call import-source, $(setuptools_scm-url), $(setuptools_scm-checksum))
-	$(call pybuild, tar -xf, setuptools_scm-$(setuptools_scm-version), , \
-	                Setuptools-scm $(setuptools_scm-version))
+	tarball=setuptools-scm-$(setuptools-scm-version).tar.lz
+	$(call import-source, $(setuptools-scm-url), $(setuptools-scm-checksum))
+	$(call pybuild, tar -xf, setuptools-scm-$(setuptools-scm-version), , \
+	                Setuptools-scm $(setuptools-scm-version), GPEP517)
 
 $(ipydir)/setuptools-rust-$(setuptools-rust-version): \
-                          $(ipydir)/setuptools-$(setuptools-version)
+                          $(ipydir)/gpep517-$(gpep517-version) \
+                          $(ipydir)/python-installer-$(python-installer-version)
 	tarball=setuptools-rust-$(setuptools-rust-version).tar.lz
 	$(call import-source, $(setuptools-rust-url), $(setuptools-rust-checksum))
 	$(call pybuild, tar -xf, setuptools-rust-$(setuptools-rust-version), , \
@@ -692,14 +985,17 @@ $(ipydir)/sip_tpv-$(sip_tpv-version): \
 	cp $(dtexdir)/sip_tpv.tex $(ictdir)/
 	echo "sip_tpv $(sip_tpv-version) \citep{sip-tpv}" > $@
 
-
-$(ipydir)/six-$(six-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/six-$(six-version): \
+                     $(ipydir)/setuptools-$(setuptools-version)
 	tarball=six-$(six-version).tar.lz
 	$(call import-source, $(six-url), $(six-checksum))
 	$(call pybuild, tar -xf, six-$(six-version), , \
-	                Six $(six-version))
+	                Six $(six-version), GPEP517)
+	echo "Six $(six-version)" > $@
 
-$(ipydir)/soupsieve-$(soupsieve-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/soupsieve-$(soupsieve-version): \
+                    $(ipydir)/setuptools-$(setuptools-version) \
+                    $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=soupsieve-$(soupsieve-version).tar.gz
 	$(call import-source, $(soupsieve-url), $(soupsieve-checksum))
 	$(call pybuild, tar -xf, soupsieve-$(soupsieve-version), , \
@@ -718,21 +1014,30 @@ $(ipydir)/uncertainties-$(uncertainties-version): $(ipydir)/numpy-$(numpy-versio
 	$(call pybuild, tar -xf, uncertainties-$(uncertainties-version), , \
 	                uncertainties $(uncertainties-version))
 
-$(ipydir)/urllib3-$(urllib3-version): $(ipydir)/setuptools-$(setuptools-version)
+$(ipydir)/urllib3-$(urllib3-version): \
+                  $(ipydir)/gpep517-$(gpep517-version) \
+                  $(ipydir)/python-installer-$(python-installer-version)
 	tarball=urllib3-$(urllib3-version).tar.gz
 	$(call import-source, $(urllib3-url), $(urllib3-checksum))
 	$(call pybuild, tar -xf, urllib3-$(urllib3-version), , \
 	                Urllib3 $(urllib3-version))
 
 $(ipydir)/webencodings-$(webencodings-version): \
-                       $(ipydir)/setuptools-$(setuptools-version)
+                       $(ipydir)/setuptools-$(setuptools-version) \
+                       $(ipydir)/setuptools-scm-$(setuptools-scm-version)
 	tarball=webencodings-$(webencodings-version).tar.gz
 	$(call import-source, $(webencodings-url), $(webencodings-checksum))
 	$(call pybuild, tar -xf, webencodings-$(webencodings-version), , \
 	                Webencodings $(webencodings-version))
 
-$(ipydir)/wheel-$(wheel-version): $(ipydir)/setuptools-$(setuptools-version)
-	tarball=wheel-$(wheel-version).tar.lz
+# As of 2025-02, this is only needed if you want 'wheel' on the command
+# line; 'setuptools' provides its own version of wheels.
+$(ipydir)/wheel-$(wheel-version): \
+                $(ipydir)/gpep517-$(gpep517-version) \
+                $(ipydir)/flit-core-$(flit-core-version) \
+                $(ipydir)/python-installer-$(python-installer-version)
+#	tarball=wheel-$(wheel-version).tar.lz
+	tarball=wheel-$(wheel-version).tar.gz
 	$(call import-source, $(wheel-url), $(wheel-checksum))
 	$(call pybuild, tar -xf, wheel-$(wheel-version), , \
-	                Wheel $(wheel-version))
+	                Wheel $(wheel-version), GPEP517)