Add fpc_ProcID type and use it for all process IDs

See https://github.com/zeldaret/tp/pull/2173

src/d/d_auction_screen.cpp

@@ -142,7 +142,7 @@ static void dAs_Create(msg_class*) {
 }
 
 /* 80160D20-80160D70       .text dAuction_screen_create__Fv */
-uint dAuction_screen_create() {
+fpc_ProcID dAuction_screen_create() {
     /* Nonmatching */
 }