Start gen defines at Gen I

include/config.h

@@ -64,13 +64,15 @@
 #define ITEM_EXPANSION
 
 // Generation constants used in configs to define behavior
-#define GEN_3 0
-#define GEN_4 1
-#define GEN_5 2
-#define GEN_6 3
-#define GEN_7 4
-#define GEN_8 5
-#define GEN_9 6
+#define GEN_1 0
+#define GEN_2 1
+#define GEN_3 2
+#define GEN_4 3
+#define GEN_5 4
+#define GEN_6 5
+#define GEN_7 6
+#define GEN_8 7
+#define GEN_9 8
 #define GEN_LATEST GEN_9
 
 // General settings

include/config/pokemon.h

@@ -25,7 +25,7 @@
 // Species-specific settings
 #define P_SHEDINJA_BALL             GEN_LATEST  // Since Gen 4, Shedinja requires a Poké Ball for its evolution. In Gen 3, Shedinja inherits Nincada's Ball.
 #define P_KADABRA_EVERSTONE         GEN_LATEST  // Since Gen 4, Kadabra can evolve even when holding an Everstone.
-#define P_SHUCKLE_BERRY_JUICE       TRUE        // In Gen 2, Shuckle had a 1/16 chance of converting Berry that it's holding into Berry Juice. Setting this to TRUE will allow to do this with an Oran Berry, which is the spiritual succesor of the Berry item.
+#define P_SHUCKLE_BERRY_JUICE       GEN_LATEST  // In Gen 2, Shuckle had a 1/16 chance of converting Berry that it's holding into Berry Juice. Enabling this will allow Shuckle to do this with an Oran Berry, which is the spiritual succesor of the Berry item.
 
 // Other settings
 #define P_CUSTOM_GENDER_DIFF_ICONS  TRUE        // If TRUE, will give more Pokémon custom icons for their female forms, i.e. Hippopotas and Hippowdon

src/battle_script_commands.c

@@ -14479,7 +14479,7 @@ static void Cmd_pickup(void)
                     SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &heldItem);
                 }
             }
-            #if P_SHUCKLE_BERRY_JUICE == TRUE
+            #if P_SHUCKLE_BERRY_JUICE == GEN_2
             else if (species == SPECIES_SHUCKLE
                 && heldItem == ITEM_ORAN_BERRY
                 && (Random() % 16) == 0)