contrib: fontconfig: remove dubious libfontconfig.la patching

Originally introduced in f1faa9d8e7 and
modified in b8fd571826. We might not even
need a HAVE_MACOSX differentiation.

contrib/src/fontconfig/rules.mak

@@ -50,7 +50,6 @@ else
 	$(MAKE) -C $< install-exec
 	$(MAKE) -C $< -C fontconfig
 	$(MAKE) -C $< -C fontconfig install-data
-	sed -e 's%/usr/lib/libiconv.la%%' -i.orig $(PREFIX)/lib/libfontconfig.la
 	cp $</fontconfig.pc $(PREFIX)/lib/pkgconfig/
 endif
 	touch $@