The existing dependencies in the extlibs directory
have been updated to use universal frameworks
for both x86_64 and arm64, allowing SFML to built
natively on the new M1 chipset
This should improve the signing process of Mac Applications.
This improves the frameworks of external dependencies used by SFML. To
patch sfml-*.framework, one would need to customised the
`MACOSX_FRAMEWORK_INFO_PLIST` cmake property and provide a custom
Info.plist file with CFBundleSupportedPlatforms property set. See
https://cmake.org/cmake/help/latest/prop_tgt/FRAMEWORK.html
This is however not required (probably) if one used dylibs instead.
Related to #1020 and #1036. Credits go to @kipbits.
