Custom skin tone preferences.

code/__DEFINES/DNA.dm

@@ -71,6 +71,11 @@
 #define MUT_EXTRA 2
 #define MUT_OTHER 3
 
+//species use_skintones defines
+#define NO_SKINTONES 0
+#define USE_SKINTONES 1
+#define USE_SKINTONES_GRAYSCALE_CUSTOM 2 //adds a "_g" suffix to limb overlays icon states if the skin_tone is a custom one.
+
 //DNA - Because fuck you and your magic numbers being all over the codebase.
 #define DNA_BLOCK_SIZE				3
 
@@ -131,9 +136,10 @@
 #define NOAROUSAL		20	//Stops all arousal effects
 #define NOGENITALS		21	//Cannot create, use, or otherwise have genitals
 #define MATRIXED		22	//if icon is color matrix'd
-#define SKINTONE		23	//uses skin tones
-#define HORNCOLOR		24
-#define WINGCOLOR		25
+#define SKINTONE		23
+#define CUSTOM_SKINTONE	24 //adds a "_g" suffix to bodypart overlays icon states
+#define HORNCOLOR		25
+#define WINGCOLOR		26
 
 //organ slots
 #define ORGAN_SLOT_BRAIN "brain"