wmctrl: support cross-compilation

Add dependencies on correct place for cross-compiling.
Fix issue where 'glib.h' cannot be found when cross-compiling.

pkgs/tools/X11/wmctrl/default.nix

···
     sha256 = "1afclc57b9017a73mfs9w7lbdvdipmf9q0xdk116f61gnvyix2np";
   };
 
-  nativeBuildInputs = [ pkg-config ];
+  strictDeps = true;
+  depsBuildBuild = [ pkg-config ];
+  nativeBuildInputs = [ glib.dev ];
   buildInputs = [ libX11 libXmu glib ];
 
   patches = [ ./64-bit-data.patch ];