libcli: add patch for gcc5

pkgs/development/libraries/libcli/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub }:
+{ stdenv, fetchFromGitHub, fetchpatch }:
 
 stdenv.mkDerivation rec {
   name = "libcli-${version}";
@@ -11,6 +11,13 @@ stdenv.mkDerivation rec {
     owner = "dparrish";
   };
 
+  patches = [
+    (fetchpatch {
+      url = https://patch-diff.githubusercontent.com/raw/dparrish/libcli/pull/21.diff;
+      sha256 = "150nm33xi3992zx8a9smjzd8zs7pavrwg1pijah6nyl22q9gxm21";
+    })
+  ];
+
   enableParallelBuilding = true;
 
   makeFlags = [ "PREFIX=$(out)" ];