fixes

include/opengl/handles/shader_handle.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include "GL/glew.h"
+
+namespace zgl
+{
+struct shader_handle
+{
+	constexpr bool operator==(const shader_handle&) const = default;
+
+	GLuint shader_id{ 0 };
+};
+}