Bugfix: Make initial_args a const char** to satisfy exec argument type warning (on Windows only)

cgminer.c

@@ -1971,7 +1971,11 @@ void kill_work(void)
 	quit(0, "Shutdown signal received.");
 }
 
-static char **initial_args;
+static
+#ifdef WIN32
+const
+#endif
+char **initial_args;
 
 static void clean_up(void);