xbase: gcc6/gcc7 patches

pkgs/development/libraries/xbase/default.nix

···
       url = "http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/dev-db/xbase/files/xbase-3.1.2-gcc47.patch?revision=1.1";
       sha256 = "1kpcrkkcqdwl609yd0qxlvp743icz3vni13993sz6fkgn5lah8yl";
     })
+    (fetchurl {
+      url = "https://gitweb.gentoo.org/repo/gentoo.git/plain/dev-db/xbase/files/xbase-3.1.2-gcc6.patch";
+      sha256 = "1994pqiip5njkcmm5czb1bg6zdldkx1mpandgmvzqrja0iacf953";
+    })
+    (fetchurl {
+      url = "https://gitweb.gentoo.org/repo/gentoo.git/plain/dev-db/xbase/files/xbase-3.1.2-gcc7.patch";
+      sha256 = "1304gn9dbdv8xf61crkg0fc8cal0h4qkyhlbqa8y618w134cxh1q";
+    })
   ];
 
   meta = {