Mainly this is following Linux to build own xml2/lzma/ssl/sqlite and linking
them all statically. This ensures the Python ssl module uses a recent openssl
version rather than a very old one shipped with macOS.
This involved getting SSL compiled from sources first, ensuring
it is a static library placement independent code. Configuration
is based on what Debian is using. CFlags required to have own
configuration file, which i didn't find a better place that next
to the corresponding CMake file.
It is OpenSSL btw.
It is set to Python via --with-openssl= configuration argument.
This works fine in a clean chroot, but having libssl-dev installed
might make Python to prefer system wide library, This was worked
around by using libssl_pic.a name for the library and modifying
setup.py. Would be cool to ensure system wide libraries are not
a problem, but official release builder is safe against this,
since it will catch possible non-static dependencies.
There is also a new map file which shadows bunch of Python
symbols. Without this Python's shared libraries might bring
conflicting symbols to Blender namespace at runtime.
Hopefully this doesn't break other platforms.
