Add rgbdscheck.asm

Makefile

@@ -61,7 +61,7 @@ clean:
 # Remove generated files except for graphics.
 .PHONY: tidy
 tidy:
-	rm -rf $(ROM) $(CORRECTEDROM) $(ROMS:.gb=.sym) $(ROMS:.gb=.map) $(OBJS) $(BUILD)/shim.asm
+	rm -rf $(ROM) $(CORRECTEDROM) $(ROMS:.gb=.sym) $(ROMS:.gb=.map) $(OBJS) $(BUILD)/shim.asm rgbdscheck.o
 
 # Visualize disassembly progress.
 .PHONY: coverage
@@ -71,6 +71,9 @@ coverage: $(ROM:.gb=.map)
 
 ### Build products
 
+rgbdscheck.o: rgbdscheck.asm
+	$(RGBASM) -o $@ $<
+
 %.map: %.gb
 
 $(CORRECTEDROM): %-correctheader.gb: %.gb
@@ -97,10 +100,10 @@ include slack/slack.mk
 
 ### Catch-all build target rules
 
-$(BUILD)/%.o: $(BUILD)/%.asm | $$(dir $$@)
+$(BUILD)/%.o: $(BUILD)/%.asm | $$(dir $$@) rgbdscheck.o
 	$(RGBASM) $(RGBASMFLAGS) $(OUTPUT_OPTION) $<
 
-$(BUILD)/%.o: %.asm | $$(dir $$@)
+$(BUILD)/%.o: %.asm | $$(dir $$@) rgbdscheck.o
 	$(RGBASM) $(RGBASMFLAGS) $(OUTPUT_OPTION) $<
 
 $(BUILD)/%.d: %.asm | $$(dir $$@) $(SCAN_INCLUDES)

rgbdscheck.asm

@@ -0,0 +1,6 @@
+IF !DEF(__RGBDS_MAJOR__) || !DEF(__RGBDS_MINOR__) || !DEF(__RGBDS_PATCH__)
+	fail "pokecrystal requires rgbds v0.7.0 or newer."
+ENDC
+IF __RGBDS_MAJOR__ == 0 && __RGBDS_MINOR__ <  7
+	fail "pokecrystal requires rgbds v0.7.0 or newer."
+ENDC