Add ARM9 exception vectors feature from @TuxSH

exceptions/arm9/Makefile

@@ -0,0 +1,47 @@
+rwildcard = $(foreach d, $(wildcard $1*), $(filter $(subst *, %, $2), $d) $(call rwildcard, $d/, $2))
+
+ifeq ($(strip $(DEVKITARM)),)
+$(error "Please set DEVKITARM in your environment. export DEVKITARM=<path to>devkitARM")
+endif
+
+include $(DEVKITARM)/3ds_rules
+
+CC := arm-none-eabi-gcc
+AS := arm-none-eabi-as
+LD := arm-none-eabi-ld
+OC := arm-none-eabi-objcopy
+
+name := arm9_exceptions
+
+dir_source := source
+dir_build := build
+
+ASFLAGS := -mcpu=arm946e-s
+CFLAGS  := -Wall -Wextra -MMD -MP -mthumb -mthumb-interwork $(ASFLAGS) -fno-builtin -std=c11 -Wno-main -O2 -flto -ffast-math
+LDFLAGS := -nostdlib
+
+objects = $(patsubst $(dir_source)/%.s, $(dir_build)/%.o, \
+          $(patsubst $(dir_source)/%.c, $(dir_build)/%.o, \
+          $(call rwildcard, $(dir_source), *.s *.c)))
+
+.PHONY: all
+all: $(name).bin
+
+.PHONY: clean
+clean:
+	@rm -rf $(dir_build)
+
+$(name).bin: $(dir_build)/$(name).elf
+	$(OC) -S -O binary $< $@
+
+$(dir_build)/$(name).elf: $(objects)
+	$(CC) $(LDFLAGS) -T linker.ld $(OUTPUT_OPTION) $^
+
+$(dir_build)/%.o: $(dir_source)/%.c
+	@mkdir -p "$(@D)"
+	$(COMPILE.c) $(OUTPUT_OPTION) $<
+
+$(dir_build)/%.o: $(dir_source)/%.s
+	@mkdir -p "$(@D)"
+	$(COMPILE.s) $(OUTPUT_OPTION) $<
+include $(call rwildcard, $(dir_build), *.d)