--- a/3rdparty/bgfx/src/bgfx.cpp
+++ b/3rdparty/bgfx/src/bgfx.cpp
@@ -3,6 +3,8 @@
  * License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
  */
 
+#include <cstddef>
+
 #include <bx/platform.h>
 #if BX_PLATFORM_WINDOWS
 // BK - Remotery needs WinSock, but on VS2015/Win10 build