Add a way to embed renderer backends code into NazaraRenderer

src/Nazara/VulkanRenderer/Export.cpp

@@ -5,6 +5,8 @@
 #include <Nazara/Prerequisites.hpp>
 #include <Nazara/VulkanRenderer/VulkanRenderer.hpp>
 
+#ifndef NAZARA_RENDERER_EMBEDDEDBACKENDS
+
 extern "C"
 {
 	NAZARA_EXPORT Nz::RendererImpl* NazaraRenderer_Instantiate()
@@ -14,6 +16,8 @@ extern "C"
 	}
 }
 
+#endif
+
 #if defined(NAZARA_PLATFORM_WINDOWS)
 #include <Nazara/Core/AntiWindows.hpp>
 #endif