xjump: patch for darwin

pkgs/games/xjump/darwin.patch

@@ -0,0 +1,21 @@
+--- xjump/src/main.c	2018-02-20 09:15:15.608807657 +0100
++++ xjump-patched/src/main.c	2018-02-20 09:15:34.148949100 +0100
+@@ -604,18 +604,6 @@
+    * optimistic privilege dropping function. */
+   setgroups(0, NULL);
+ 
+-  if (setresgid(-1, realgid, realgid) != 0) {
+-    perror("Could not drop setgid privileges.  Aborting.");
+-    exit(1);
+-  }
+-
+-  /* Dropping user privileges must come last.
+-   * Otherwise we won't be able to drop group privileges anymore */
+-  if (setresuid(-1, realuid, realuid) != 0) {
+-    perror("Could not drop setuid privileges.  Aborting.");
+-    exit(1);
+-  }
+-
+   /* From now on we run with regular user privileges */
+ 
+   static XtActionsRec a_table[] = {

pkgs/games/xjump/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, autoconf, automake, libX11, libXt, libXpm, libXaw, localStateDir?"/var" }:
+{ stdenv, buildPlatform, fetchFromGitHub, autoconf, automake, libX11, libXt, libXpm, libXaw, localStateDir?null }:
 
 stdenv.mkDerivation rec {
   name = "xjump-${version}";
@@ -12,7 +12,12 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ autoconf automake ];
   buildInputs = [ libX11 libXt libXpm libXaw ];
   preConfigure = "autoreconf --install";
-  configureFlags = ["--localstatedir=${localStateDir}"];
+  patches = if buildPlatform.isDarwin then [ ./darwin.patch ] else [];
+  configureFlags =
+    if localStateDir != null then
+      ["--localstatedir=${localStateDir}"]
+    else
+      [];
 
   meta = with stdenv.lib; {
     description = "The falling tower game";