Replace TC macros with an enum that automatically counts up

Also fixes TC_DASHMODE not being accessible to Lua.

src/lua_hudlib.c

@@ -896,8 +896,10 @@ static int libd_getColormap(lua_State *L)
 	else if (lua_type(L, 1) == LUA_TNUMBER) // skin number
 	{
 		skinnum = (INT32)luaL_checkinteger(L, 1);
-		if (skinnum < TC_BLINK || skinnum >= MAXSKINS)
-			return luaL_error(L, "skin number %d is out of range (%d - %d)", skinnum, TC_BLINK, MAXSKINS-1);
+		if (skinnum >= MAXSKINS)
+			return luaL_error(L, "skin number %d is out of range (>%d)", skinnum, MAXSKINS-1);
+		else if (skinnum < 0 && skinnum > TC_DEFAULT)
+			return luaL_error(L, "translation colormap index is out of range");
 	}
 	else // skin name
 	{

src/r_draw.h

@@ -106,13 +106,17 @@ extern lumpnum_t viewborderlump[8];
 
 #define GTC_CACHE 1
 
-#define TC_DEFAULT    -1
-#define TC_BOSS       -2
-#define TC_METALSONIC -3 // For Metal Sonic battle
-#define TC_ALLWHITE   -4 // For Cy-Brak-demon
-#define TC_RAINBOW    -5 // For single colour
-#define TC_BLINK      -6 // For item blinking, according to kart
-#define TC_DASHMODE   -7 // For Metal Sonic's dashmode
+enum
+{
+	TC_BOSS       = INT8_MIN,
+	TC_METALSONIC, // For Metal Sonic battle
+	TC_ALLWHITE,   // For Cy-Brak-demon
+	TC_RAINBOW,    // For single colour
+	TC_BLINK,      // For item blinking, according to kart
+	TC_DASHMODE,   // For Metal Sonic's dashmode
+
+	TC_DEFAULT
+};
 
 // Custom player skin translation
 // Initialize color translation tables, for player rendering etc.