Avoid encoding build paths into sources used for floating point on powerpc.
(MACHINE=qemuppc bitbake libgcc).

Upstream-Status: Submitted [https://gcc.gnu.org/pipermail/gcc-patches/2022-August/599882.html]
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

Index: gcc-12.1.0/libgcc/config/rs6000/t-float128
===================================================================
--- gcc-12.1.0.orig/libgcc/config/rs6000/t-float128
+++ gcc-12.1.0/libgcc/config/rs6000/t-float128
@@ -103,7 +103,7 @@ $(ibm128_dec_objs)	: INTERNAL_CFLAGS +=
 $(fp128_softfp_src) : $(srcdir)/soft-fp/$(subst -sw,,$(subst kf,tf,$@)) $(fp128_dep)
 	@src="$(srcdir)/soft-fp/$(subst -sw,,$(subst kf,tf,$@))"; \
 	echo "Create $@"; \
-	(echo "/* file created from $$src */"; \
+	(echo "/* file created from `basename $$src` */"; \
 	 echo; \
 	 sed -f $(fp128_sed) < $$src) > $@