bpo-21536: C extensions are no longer linked to libpython (GH-12946)
On Unix, C extensions are no longer linked to libpython.
It is now possible to load a C extension built using a shared library
Python with a statically linked Python.
When Python is embedded, libpython must not be loaded with
RTLD_LOCAL, but RTLD_GLOBAL instead. Previously, using RTLD_LOCAL, it
was already not possible to load C extensions which were not linked
to libpython, like C extensions of the standard library built by the
"*shared*" section of Modules/Setup.
distutils, python-config and python-config.py have been modified.