gcc: Revive the no-sys-dirs patch

For now, we don't NATIVE_SYSTEM_HEADER_DIR because it breaks the
build. However, it points to Glibc in the Nix store (not /usr/include)
so it's kind of okay.

pkgs/development/compilers/gcc/4.8/default.nix

@@ -64,6 +64,7 @@ let version = "4.8.3";
     patches = []
       ++ optional enableParallelBuilding ./parallel-bconfig.patch
       ++ optional (cross != null) ./libstdc++-target.patch
+      ++ optional noSysDirs ./no-sys-dirs.patch
       # The GNAT Makefiles did not pay attention to CFLAGS_FOR_TARGET for its
       # target libraries and tools.
       ++ optional langAda ./gnat-cflags.patch