Add a gcc driver for SerenityOS
This patch adds support for the *-*-serenity target to gcc.
It specifies which flags need to be passed to the linker, defines the
serenity macro, sets the correct underlying type of size_t and
ptrdiff_t, and enables IFUNCs.
fixincludes: Skip for SerenityOS targets
fixincludes is responsible for fixing mistakes in system headers that
rely in compiler extensions that GCC doesn't support or cause errors in
C++ mode.
Our headers don't have such problems, so this hack is of no use for us.
libgcc: Build for SerenityOS
This patch enables building gcc's own C runtime files, and sets up exception handling support.
libgcc: Do not link libgcc_s to LibC
The toolchain is built before LibC, so linking to the C runtime library would fail.
i386: Disable math errno for SerenityOS
SerenityOS uses exceptions for math error handling, which allows the compiler to do more optimizations on calls to math functions. This patch has the effect of setting -fno-math-errno by default.
libstdc++: Support SerenityOS
During the toolchain build, SerenityOS libraries are not available, so we have to manually tell libstdc++ about what our LibC supports.
In most places, we take the Newlib code paths.