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/src/pthreads.mk	Fri Sep 01 23:20:44 2017 -0700
+++ b/src/pthreads.mk	Mon Jul 31 16:53:21 2017 -0400
@@ -16,6 +16,12 @@
 
 ifeq ($(MXE_SYSTEM)$(MXE_NATIVE_BUILD),mingwno)
 define $(PKG)_BUILD
+    # apply the mingw-w64 patches to the mingw sources
+    $(foreach PKG_PATCH,$(sort $(wildcard $(TOP_DIR)/src/mingw-w64-*.patch)),
+      (cd '$(1)' && $(PATCH) -p1 -u) < $(PKG_PATCH))
+    $(foreach PKG_PATCH,$(sort $(wildcard $(TOP_DIR)/src/$(MXE_SYSTEM)-mingw-w64-*.patch)),
+      (cd '$(1)' && $(PATCH) -p1 -u) < $(PKG_PATCH))
+
     cd '$(1)/mingw-w64-libraries/winpthreads' && ./configure \
         $(HOST_AND_BUILD_CONFIGURE_OPTIONS) \
         --prefix='$(HOST_PREFIX)' \