Align Makefile with SA2 more

Makefile

@@ -87,7 +87,7 @@ FORMAT    := clang-format-13
 ### TOOLS ###
 GFX 	  := tools/gbagfx/gbagfx$(EXE)
 ENT_POS   := tools/entity_positions/entity_positions$(EXE)
-AIF	      := tools/aif2pcm/aif2pcm$(EXE)
+AIF		  := tools/aif2pcm/aif2pcm$(EXE)
 MID2AGB   := tools/mid2agb/mid2agb$(EXE)
 SCANINC   := tools/scaninc/scaninc$(EXE)
 PREPROC	  := tools/preproc/preproc$(EXE)
@@ -203,6 +203,10 @@ FORMAT_H_PATHS   := $(shell find . -name "*.h" ! -path '*/build/*' ! -path '*/ex
 CPPFLAGS ?= $(INCLUDE_CPP_ARGS) -D $(GAME_REGION)
 CC1FLAGS ?= -Wimplicit -Wparentheses -Werror
 
+ifneq ($(GAME_VARIANT), DEFAULT)
+	CPPFLAGS += -D $(GAME_VARIANT)
+endif
+
 # These have to(?) be defined this way, because
 # the C-preprocessor cannot resolve stuff like:
 # #if (PLATFORM == gba), where PLATFORM is defined via -D.

config.mk

@@ -53,6 +53,7 @@ endif
 # Default game variables
 GAME_REVISION ?= 0
 GAME_REGION   ?= EUROPE
+GAME_VARIANT  ?= DEFAULT
 DEBUG         ?= 0
 
 # For gbafix