gcc: update to 7.1 with tools * src/build-gcc.mk: update version 7.1.0 * src/cloog.mk: update 0.18.4 * src/gmp.mk: update 6.1.2 * src/isl.mk: update 0.16.1, add no-undefined flag * src/mpfr.mk: update 3.1.6 * src/native-gcc.mk: update 7.1.0 * src/isl-1-fixes.patch: removed file * dist-files.mk: remove reference to patch files, add mingw-w64 patch * src/build-gcc-1-mingw-float.patch: removed patch * src/native-gcc-1-mingw-float.patch: removed patch * src/build-gcc-2-intrinsics.patch: removed patch * src/native-gcc-2-intrinsics.patch: removed patch * src/mingw-w64.mk: update to 5.0.2 * src/gcc-1-mingw-float.patch: remove patch * src/gcc-2-darwin-no-pie.patch: remove patch * src/mingw-w64-2-pthreads.patch: new file * src/pthreads.mk: apply mingw patches to mingw sources before running configure

--- a/Makefile.in	1995-08-16 20:54:29.000000000 -0400
+++ b/Makefile.in	2012-12-05 11:45:11.124478718 -0500
@@ -75,8 +75,6 @@
 	$(INSTALL_DATA) libtermcap.a $(libdir)/libtermcap.a
 	-$(RANLIB) $(libdir)/libtermcap.a
 	cd $(srcdir); $(INSTALL_DATA) termcap.h $(includedir)/termcap.h
-	-cd $(srcdir); test -z "$(oldincludedir)" || \
-	  $(INSTALL_DATA) termcap.h $(oldincludedir)/termcap.h
 	cd $(srcdir); for f in termcap.info*; \
 	do $(INSTALL_DATA) $$f $(infodir)/$$f; done