Add Haiku support

This pushes to Khronos the change done by Alexander von Gluck IV in Mesa
commit 400b833592d9aad7b2c4627a897380642d52189f "egl: Add Haiku code and
support" [1].

[1] https://cgit.freedesktop.org/mesa/mesa/commit/?id=400b833592d9aad7b2c4627a897380642d52189f
diff --git a/api/EGL/eglplatform.h b/api/EGL/eglplatform.h
index f5a22bc..2247eb8 100644
--- a/api/EGL/eglplatform.h
+++ b/api/EGL/eglplatform.h
@@ -108,6 +108,14 @@
 typedef Pixmap   EGLNativePixmapType;
 typedef Window   EGLNativeWindowType;
 
+#elif defined(__HAIKU__)
+
+#include <kernel/image.h>
+
+typedef void              *EGLNativeDisplayType;
+typedef khronos_uintptr_t  EGLNativePixmapType;
+typedef khronos_uintptr_t  EGLNativeWindowType;
+
 #else
 #error "Platform not recognized"
 #endif