splint: Add darwin support

pkgs/development/tools/analysis/splint/darwin.patch

@@ -0,0 +1,13 @@
+diff --git a/src/osd.c b/src/osd.c
+index ebe214a..4ba81d5 100644
+--- a/src/osd.c
++++ b/src/osd.c
+@@ -516,7 +516,7 @@ osd_getPid ()
+ # if defined (WIN32) || defined (OS2) && defined (__IBMC__)
+   int pid = _getpid ();
+ # else
+-  __pid_t pid = getpid ();
++  pid_t pid = getpid ();
+ # endif
+ 
+   return (int) pid;

pkgs/development/tools/analysis/splint/default.nix

@@ -8,7 +8,7 @@ stdenv.mkDerivation rec {
     sha256 = "02pv8kscsrkrzip9r08pfs9xs98q74c52mlxzbii6cv6vx1vd3f7";
   };
 
-  patches = [ ./tmpdir.patch ];
+  patches = [ ./tmpdir.patch ] ++ stdenv.lib.optional stdenv.isDarwin ./darwin.patch;
 
   buildInputs = [ flex ];
 
@@ -27,6 +27,6 @@ stdenv.mkDerivation rec {
     '';
 
     license = licenses.gpl2Plus;
-    platforms = platforms.linux;
+    platforms = platforms.unix;
   };
 }