toolchain: Replace __attribute__((__unused__)) with __UNUSED

Abstracting this allows for the possibility of other compilers to have their
own implementation of marking a variable as potentially unused without using
the __attribute__ keyword (which is not supported on all compilers).

Signed-off-by: Peter Mitsis <peter.mitsis@gmail.com>

Author: PeterMitsis

code/ai/aiturret.cpp

@@ -1377,7 +1377,7 @@ void turret_ai_update_aim(ai_info *aip, object *En_Objp, ship_subsys *ss)
  */
 int aifft_rotate_turret(ship *shipp, int parent_objnum, ship_subsys *ss, object *objp, object *lep, vec3d *predicted_enemy_pos, vec3d *gvec)
 {
-	int ret_val __attribute__((__unused__)) = 0; // to be used in future, see comment @ end of function
+	int ret_val __UNUSED = 0; // to be used in future, see comment @ end of function
 
 	if (ss->turret_enemy_objnum != -1) {
 		model_subsystem *tp = ss->system_info;

code/freespace2/freespace.cpp

@@ -1265,7 +1265,7 @@ void game_loading_callback_close()
 	// Make sure bar shows all the way over.
 	game_loading_callback(COUNT_ESTIMATE);
 
-	int real_count __attribute__((__unused__)) = game_busy_callback( NULL );
+	int real_count __UNUSED = game_busy_callback( NULL );
  	Mouse_hidden = 0;
 
 	Game_loading_callback_inited = 0;
@@ -1429,7 +1429,7 @@ int game_start_mission()
 {
 	mprintf(( "=================== STARTING LEVEL LOAD ==================\n" ));
 
-	int s1 __attribute__((__unused__)) = timer_get_milliseconds();
+	int s1 __UNUSED = timer_get_milliseconds();
 
 	// clear post processing settings
 	gr_post_process_set_defaults();
@@ -1486,7 +1486,7 @@ int game_start_mission()
 
 	bm_print_bitmaps();
 
-	int e1 __attribute__((__unused__)) = timer_get_milliseconds();
+	int e1 __UNUSED = timer_get_milliseconds();
 
 	mprintf(("Level load took %f seconds.\n", (e1 - s1) / 1000.0f ));
 
@@ -1745,7 +1745,7 @@ char full_path[1024];
  */
 void game_init()
 {
-	int s1 __attribute__((__unused__)), e1 __attribute__((__unused__));
+	int s1 __UNUSED, e1 __UNUSED;
 	const char *ptr;
 	char whee[MAX_PATH_LEN];
 

code/fs2netd/fs2netd_client.cpp

@@ -737,7 +737,7 @@ static void fs2netd_handle_messages()
 
 			case PCKT_SLIST_REPLY: {
 				int numServers = 0;
-				int svr_flags __attribute__((__unused__)); // gcc [-Wunused-but-set-variable] doesn't like MACROs
+				int svr_flags __UNUSED; // gcc [-Wunused-but-set-variable] doesn't like MACROs
 				ushort svr_port;
 				char svr_ip[16];
 				active_game ag;

code/fs2netd/tcp_client.cpp

@@ -218,7 +218,7 @@ int FS2NetD_GetPlayerData(const char *player_name, player *pl, bool can_create,
 		uint rc_total = 0;
 		ubyte reply_type = 0;
 		int si_index = 0;
-		ushort bogus __attribute__((unused));
+		ushort bogus __UNUSED;
 		ushort num_type_kills = 0, num_medals = 0;
 		char ship_name[NAME_LENGTH];
 		int idx;
@@ -489,8 +489,8 @@ int FS2NetD_Login(const char *username, const char *password, bool do_send)
 		int rc;
 		uint rc_total = 0;
 		ubyte login_status = 0;
-		int sid __attribute__((unused));
-		short pilots __attribute__((unused));
+		int sid __UNUSED;
+		short pilots __UNUSED;
 
 		do {
 			rc = FS2NetD_GetData(buffer+rc_total, sizeof(buffer)-rc_total);

code/globalincs/toolchain/clang.h

@@ -20,6 +20,8 @@
 #define SCP_FORMAT_STRING
 #define SCP_FORMAT_STRING_ARGS(x,y)  __attribute__((format(printf, x, y)))
 
+#define __UNUSED __attribute__((__unused__))
+
 #ifdef NO_RESTRICT_USE
 #	define RESTRICT
 #else

code/globalincs/toolchain/gcc.h

@@ -20,6 +20,8 @@
 #define SCP_FORMAT_STRING
 #define SCP_FORMAT_STRING_ARGS(x,y)  __attribute__((format(printf, x, y)))
 
+#define __UNUSED __attribute__((__unused__))
+
 #ifdef NO_RESTRICT_USE
 #   define RESTRICT
 #else

code/globalincs/toolchain/mingw.h

@@ -20,6 +20,8 @@
 #define SCP_FORMAT_STRING
 #define SCP_FORMAT_STRING_ARGS(x,y)  __attribute__((format(printf, x, y)))
 
+#define __UNUSED __attribute__((__unused__))
+
 #ifdef NO_RESTRICT_USE
 #   define RESTRICT
 #else

code/globalincs/toolchain/msvc.h

@@ -23,6 +23,7 @@
 #define SCP_FORMAT_STRING_ARGS(x,y)
 
 #define __attribute__(x)
+#define __UNUSED
 
 #ifdef NO_RESTRICT_USE
 #   define RESTRICT

code/pilotfile/csg.cpp

@@ -1111,7 +1111,7 @@ void pilotfile::csg_read_settings()
 
 	if (csg_ver < 3) {
 		// detail
-		int dummy  __attribute__((__unused__)) = cfread_int(cfp);
+		int dummy  __UNUSED = cfread_int(cfp);
 		dummy = cfread_int(cfp);
 		dummy = cfread_int(cfp);
 		dummy = cfread_int(cfp);
@@ -1152,7 +1152,7 @@ void pilotfile::csg_write_settings()
 void pilotfile::csg_read_controls()
 {
 	int idx, list_size;
-	short id1, id2, id3 __attribute__((__unused__));
+	short id1, id2, id3 __UNUSED;
 
 	list_size = (int)cfread_ushort(cfp);
 

code/pilotfile/plr.cpp

@@ -600,7 +600,7 @@ void pilotfile::plr_write_stats_multi()
 void pilotfile::plr_read_controls()
 {
 	int idx, list_size, list_axis;
-	short id1, id2, id3 __attribute__((__unused__));
+	short id1, id2, id3 __UNUSED;
 	int axi, inv;
 
 	list_size = (int)cfread_ushort(cfp);