In order for Sage to run on older macOS systems we specify a minimum target of 10.12 and we need to disable AVX2 instructions. (There are Intel CPUs which are new enough to run Big Sur yet do not support AVX2.) We can do this for givaro with SAGE_FAT_BINARY=yes but that does not work with gmp because the gmp spkg ignores SAGE_FAT_BINARY on macOS. So we need to also set GMP_CONFIGURE. Also, the givaro package disables sse and sse2 when SAGE_FAT_BINARY is set, but that is unnecessary (according to conda) so we modify the spkg. Setting the minimum OS version target has become trickier now that Apple's ld accepts the new -platform_version option. Just using -mmacosx-version-min=10.9 is no longer sufficient. A number of libraries, including libreadline and libhistory will be built with the minimum target set to 11.0 instead of 10.9. This can be worked around by setting *both* the CFLAGS and LDFLAGS environment variables. Also, in order to have a working distutils it is necessary to provide the same information in the MACOS_DEPLOYMENT_TARGET environment variable. In order to avoid illegal instruction crashes, we currently modify the spkg-install.in files for the givaro and openblas packages. The portability.patch should be applied in the sage git repository before building. Below are the build commands we use. We use the "build" make target because we do not need to build documentation. (The app uses the documentation on the web.) $ export GMP_CONFIGURE="--enable-fat" $ export SAGE_FAT_BINARY="yes" $ export CFLAGS="-mmacosx-version-min=10.12 -mno-avx2 -mno-bmi2" $ export LDFLAGS="-Wl,-platform_version,macos,10.12,11.3" $ export MACOSX_DEPLOYMENT_TARGET="10.12" $ export MAKE="make -j8" $ ./configure --without-system-python3 $ make build
