Macro cleanup: PROTO

Regarding dict_lookup() in eval.c: both definitions are the same, the
only difference being the spacing between the indirection operator and
the indentation level.

src/nvim/regexp.c

@@ -3228,7 +3228,7 @@ static garray_T backpos = GA_EMPTY_INIT_VALUE;
 #define REGSTACK_INITIAL        2048
 #define BACKPOS_INITIAL         64
 
-#if defined(EXITFREE) || defined(PROTO)
+#if defined(EXITFREE)
 void free_regexp_stuff(void)
 {
   ga_clear(&regstack);