diff --git a/lib/vk_funcs.h b/lib/vk_funcs.h
index 078e91ce9f..8f73fbd859 100644
--- a/lib/vk_funcs.h
+++ b/lib/vk_funcs.h
@@ -21,7 +21,9 @@
 #ifndef _VK_FUNCS_H_
 #define _VK_FUNCS_H_
 
+#if !defined(VK_NO_PROTOTYPES)
 #define VK_NO_PROTOTYPES
+#endif
 
 #include "vulkan/vk_platform.h"
 #include "vulkan/vulkan_core.h"