Fix ABI compatibility with libc compiled with old tools on powerpc.

Fix ABI compatibility with libc compiled with old tools on powerpc.

	Changes contributed by Franz Sirl <Franz.Sirl-kernel@lauterbach.com>
	and Jack Howarth <howarth@bromo.med.uc.edu>.
	* sysdeps/powerpc/Makefile [$(have-protected) = yes]
	(CPPFLAGS-divdi3.c, CPPFLAGS-libgcc-compat.S): New variables,
	pass -DHAVE_DOT_HIDDEN for these files.
	* sysdeps/powerpc/Versions (libc: GLIBC_2.0): Added __floatdidf,
	__floatdisf.
	* sysdeps/powerpc/divdi3.c: New file.
	* sysdeps/powerpc/libgcc-compat.S: New file, replacement for ...
	* sysdeps/powerpc/libgcc-compat.c: ... this, file removed.