Declare all dsfs as a dedicated type name 'DSF'.

In this commit, 'DSF' is simply a typedef for 'int', so that the new
declaration form 'DSF *' translates to the same type 'int *' that dsfs
have always had. So all we're doing here is mechanically changing type
declarations throughout the code.

map.c

@@ -1725,7 +1725,7 @@ static const char *parse_edge_list(const game_params *params,
     bool state;
     const char *p = *desc;
     const char *err = NULL;
-    int *dsf = snew_dsf(wh);
+    DSF *dsf = snew_dsf(wh);
 
     pos = -1;
     state = false;