wmaker: Cleaned dangerous function prototype usage

- remove extern declaration in source file, use header instead

- add inclusion of header defining the functions of the file to
get the compiler to cross-check them

- marked static the functions that should not be visible ouside
their file

src/osdep_stub.c

@@ -4,6 +4,7 @@
 #include <WINGs/WUtil.h>
 
 #include "wconfig.h"
+#include "funcs.h"
 
 Bool GetCommandForPid(int pid, char ***argv, int *argc)
 {