This change enables cross-compilation for the pyproject-build-system, at the same time paving the way to fix the longstanding bug #25235 (Wrapped python programs get native-inputs in PYTHONPATH), by keeping the distinction between native and host (regular) inputs even when not cross-compiling. A unified builder is used, which departs from the other build systems (which use one builder for the native build and another one for the cross build, where implemented). If this change is accepted, there would be adjustments needed to some of the ~120 Python packages using pyproject (looking for a native inputs now needs to be done using the 'native-inputs' instead of 'inputs' argument even in the native compilation mode). Over time I think it'd make sense to migrate more build systems to use this scheme, since it gives more control as to what inputs go into the wrapper. A demo package, python-pycryptodome, that contains C extensions is adjusted so that it can be cross-compiled using this new build system. It is provided separately as it would need to go to core-updates. Changes in v2: - Rebase Maxim Cournoyer (1): build: Enable cross-compilation for pyproject-build-system. guix/build-system/pyproject.scm | 115 ++++++++++++++--------- guix/build/pyproject-build-system.scm | 126 +++++++++++++++++++++++--- guix/packages.scm | 46 +++++----- 3 files changed, 210 insertions(+), 77 deletions(-) base-commit: 3a1b18aa4540e6f96ded0a98dd907a8033262582 -- 2.39.1