if prototype is declared static make function static to match

Today, a compiler was encountered that considered it an error
to have the prototype declared static and the function body
not

src/makemon.c

@@ -1033,7 +1033,7 @@ newmextra()
     return mextra;
 }
 
-boolean
+STATIC_OVL boolean
 makemon_rnd_goodpos(mon, gpflags, cc)
 struct monst *mon;
 unsigned gpflags;