[libc][doc] Update compiler

[sivachandra]

libc/docs/compiler_support.rst

14

Nit: "build the 'libc`" project.

libc/docs/compiler_support.rst

 .. _compiler_support:
 
 ================
 Compiler Support
 ================
 
-As of now only ``Clang`` is fully supported.
+``LLVM libc`` compiles from both ``Clang`` and ``GCC`` but for maximum performance we recommand using ``Clang``.
 
-We are in the process of supporting ``GCC`` but some memory function implementations rely on `compiler intrinsics`__ that are not currently available in ``GCC``.
+Indeed, some memory function implementations rely on `compiler intrinsics`__ that are not currently available in ``GCC``.
 As such we cannot guarantee optimal performance for these functions.
 
 .. __: https://clang.llvm.org/docs/LanguageExtensions.html#guaranteed-inlined-copy
 
+For platforms where only ``GCC`` is natively available but maximum performance is required it is possible to bootstrap ``Clang`` with ``GCC`` and then use ``Clang`` to build ``LLVM libc``.
+
 Minimum version
 ===============
 
  - ``Clang 11``
+ - ``GCC 12.2```