build: Add nxdk Makefile

Makefile.xbox

@@ -0,0 +1,21 @@
+SDL_DIR = $(NXDK_DIR)/lib/sdl/SDL2
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/cpuinfo/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/events/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/file/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/render/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/render/software/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/stdlib/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/thread/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/thread/generic/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/timer/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/timer/dummy/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/video/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/video/xbox/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/video/yuv2rgb/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/libm/*.c)
+SDL_SRCS += $(wildcard $(SDL_DIR)/src/atomic/*.c)
+
+SRCS += $(SDL_SRCS)
+CFLAGS += -I$(SDL_DIR)/include \
+          -DXBOX