Make X11 as windowing system opt-in.
Fixes #52
diff --git a/api/EGL/eglplatform.h b/api/EGL/eglplatform.h
index 4cba6a1..0bc2cb9 100644
--- a/api/EGL/eglplatform.h
+++ b/api/EGL/eglplatform.h
@@ -110,7 +110,7 @@
typedef intptr_t EGLNativeWindowType;
typedef intptr_t EGLNativePixmapType;
-#elif defined(__unix__) || defined(__APPLE__)
+#elif defined(__unix__) || defined(USE_X11)
/* X11 (tentative) */
#include <X11/Xlib.h>
@@ -120,6 +120,12 @@
typedef Pixmap EGLNativePixmapType;
typedef Window EGLNativeWindowType;
+#elif defined(__APPLE__)
+
+typedef int EGLNativeDisplayType;
+typedef void *EGLNativeWindowType;
+typedef void *EGLNativePixmapType;
+
#elif defined(__HAIKU__)
#include <kernel/image.h>