I was just made aware by @mattip that some Python distributions have -g in sysconfig.get_config_vars('CFLAGS'), and thus include debug symbols (including the versions in the manylinux images, it seems). The reason for this apparently is that these are then stripped before packed in the Debian/Fedora/... package managers (and often the symbols themselves are added as separate package for debugging).

The thing about building wheels is that these sysconfig are used when building wheels. So should we somehow strip symbols as well, or add -Wl,-strip-all to the build flags, or ... ?