gcompat: Add recipe

This is a compat library which helps running pre-compiled binaries which were
compiled for glibc but needs to run on musl systems, this is quite
common case where pre-existing binaries are supplied and can not be
recompiled immediately

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>