Also target MacOS 13 for arm64 as MacPorts seems to have lost
its MacOS 12 builder.
Upgrade cctools-port used by osxcross to latest version to let it handle
objective-C constructs used by MacPorts packages.
Also refresh the patches.
Newer Apple SDK expect __ENVIRONMENT_OS_VERSION_MIN_REQUIRED__ to be
defined which LLVM before 17 don't do.
By upgrading to newer LLVM, we raise a bug in libpng which has not been
fixed in the version we use.
Finally update osxcross to take the correct compiler-rt branch.
Updating SDK implies to update LLVM to version 16 as it fails to build
with older versions (commit f4be5ed6a3fef0b2b0c60b29e1c0638926638d28).
LLVM version 16 triggers an incompatibility between compiler-rt (which
uses C++17 features) and the old i386 MacOS SDK.
This new compiler-rt also needs CMake helpers and new arguments to
properly build as we wish.
GCW0 toolchain can't be built anymore as Mesa build requires Python 2
which is not available anymore.
Helper packages got upgraded and configure arguments and several
patches must be updated.
New GCC defaults to a too modern C++ version to compile old GCC.
Debian now provides a modern enough CLang hence switching to it.
Le Philousophe