diff --git a/libavcodec/x86/hevcdsp.h b/libavcodec/x86/hevcdsp.h
index 0a52a95519..c5a64c708a 100644
--- a/libavcodec/x86/hevcdsp.h
+++ b/libavcodec/x86/hevcdsp.h
@@ -25,6 +25,7 @@
 #ifndef AVCODEC_X86_HEVCDSP_H
 #define AVCODEC_X86_HEVCDSP_H
 
+#include <stddef.h>
 #include <stdint.h>
 
 #define PEL_LINK(dst, idx1, idx2, idx3, name, D, opt) \