use -Wunused-parameter with gcc for consistency with MSVC and other compilers which warn about this; fix the uncovered warnings in wxGTK

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@49376 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/utilsgtk.cpp

@@ -245,6 +245,10 @@ const gchar *wx_pango_version_check (int major, int minor, int micro)
 
     return "can't check";
 #else // !PANGO_VERSION_MAJOR
+    wxUnusedVar(major);
+    wxUnusedVar(minor);
+    wxUnusedVar(micro);
+
     return "too old headers";
 #endif
 }