Fix SDL2 include directives

src/api/system.c

@@ -1,4 +1,4 @@
-#include <SDL2/SDL.h>
+#include <SDL.h>
 #include <stdbool.h>
 #include <ctype.h>
 #include <dirent.h>

src/main.c

@@ -1,5 +1,5 @@
 #include <stdio.h>
-#include <SDL2/SDL.h>
+#include <SDL.h>
 #include "api/api.h"
 #include "renderer.h"
 

src/renderer.h

@@ -1,7 +1,7 @@
 #ifndef RENDERER_H
 #define RENDERER_H
 
-#include <SDL2/SDL.h>
+#include <SDL.h>
 #include <stdint.h>
 
 typedef struct RenImage RenImage;