Merge pull request #325 from lawadr/use-alignof

Change __alignof to alignof
diff --git a/include/vk_mem_alloc.h b/include/vk_mem_alloc.h
index 40c1f7c..2ef9cd9 100644
--- a/include/vk_mem_alloc.h
+++ b/include/vk_mem_alloc.h
@@ -2806,7 +2806,7 @@
 #endif
 
 #ifndef VMA_ALIGN_OF
-   #define VMA_ALIGN_OF(type)       (__alignof(type))
+   #define VMA_ALIGN_OF(type)       (alignof(type))
 #endif
 
 #ifndef VMA_SYSTEM_ALIGNED_MALLOC