diff --git a/include/constants/battle_config.h b/include/constants/battle_config.h
index a484b9dbcd..b2fdc6b365 100644
--- a/include/constants/battle_config.h
+++ b/include/constants/battle_config.h
@@ -1,8 +1,6 @@
 #ifndef GUARD_CONSTANTS_BATTLE_CONFIG_H
 #define GUARD_CONSTANTS_BATTLE_CONFIG_H
 
-#define BATTLE_ENGINE
-
 // Species with peculiar battle effects.
 #ifndef POKEMON_EXPANSION
     #define SPECIES_DIALGA            0
diff --git a/include/global.h b/include/global.h
index f283db357e..caa0594897 100644
--- a/include/global.h
+++ b/include/global.h
@@ -118,6 +118,12 @@
     f;                       \
 })
 
+// Branch defines: Used by other branches to detect each other.
+// Each define must be here for each of RHH's branch you have pulled.
+// e.g. If you have both the battle_engine and pokemon_expansion branch,
+//      then both BATTLE_ENGINE and POKEMON_EXPANSION must be defined here.
+#define BATTLE_ENGINE
+
 #define ROUND_BITS_TO_BYTES(numBits)(((numBits) / 8) + (((numBits) % 8) ? 1 : 0))
 
 #define DEX_FLAGS_NO (ROUND_BITS_TO_BYTES(NUM_SPECIES))