Use wxDELETE() and wxDELETEA() when possible.

Use wxDELETE[A]() functions which automatically NULL out their arguments after
deleting them instead of doing it manually.

Closes #9685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64656 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/fontutil.cpp

@@ -1465,9 +1465,7 @@ bool wxFontModule::OnInit()
 
 void wxFontModule::OnExit()
 {
-    delete g_fontHash;
-
-    g_fontHash = NULL;
+    wxDELETE(g_fontHash);
 }
 
 #endif // GTK 2.0/1.x