--- a/src/vec.h
+++ b/src/vec.h
@@ -41,7 +41,12 @@
 #include "vec_neon.h"
 #else
 
-#include "os_support.h"
+#include <string.h>
+
+/** Set n elements of dst to zero */
+#ifndef OVERRIDE_OPUS_CLEAR
+#define OPUS_CLEAR(dst, n) (memset((dst), 0, (n)*sizeof(*(dst))))
+#endif
 
 #define MAX_INPUTS (2048)