SDL Compile Error

main.cpp

#include <SDL/SDL.h>

#include <iostream>

#ifdef _WIN32
#include <windows.h>
#endif

SDL_Surface* DisplaySurface = NULL;

bool Running = true;

void process_event(SDL_Event* event) {
	switch(event->type){
		case SDL_QUIT:
			Running = false;
			break;
		default:
			break;
	}
}

void init_sdl() {
	SDL_Init(SDL_INIT_EVERYTHING);

	DisplaySurface = SDL_SetVideoMode(1000, 600, 32, SDL_HWSURFACE | SDL_DOUBLEBUF);
}

void init_game() {

}

void draw_game() {

}

void run_game() {
	SDL_Event Event;
	while (Running) {
		while (SDL_PollEvent(&Event)) {
			process_event(&Event);
		}

		draw_game();

		SDL_Flip(DisplaySurface);
	}
}

void cleanup_game() {

}


int main(int argc, char** argv) {
	init_sdl();

	init_game();

	run_game();

	cleanup_game();
}

Makefile Output

mingw32-g++ -c -D_GNU_SOURCE=1 -Dmain=SDL_main src/main.cpp -o obj/main.o
mingw32-g++ -lmingw32 -lSDLmain -lSDL -mwindows obj/main.o -o bin/game.exe
obj/main.o:main.cpp:(.text+0x4e): undefined reference to `SDL_SetVideoMode'
obj/main.o:main.cpp:(.text+0x7b): undefined reference to `SDL_PollEvent'
obj/main.o:main.cpp:(.text+0x91): undefined reference to `SDL_Flip'
collect2: ld returned 1 exit status
mingw32-make: *** [build] Error 1