Update intrin.h

Author: gmh5225

clang/lib/Headers/intrin.h

@@ -567,6 +567,8 @@ unsigned int _CountLeadingZeros(unsigned long);
 unsigned int _CountLeadingZeros64(unsigned _int64);
 unsigned int _CountOneBits(unsigned long);
 unsigned int _CountOneBits64(unsigned __int64);
+
+void __cdecl __prefetch(void *);
 #endif
 
 /*----------------------------------------------------------------------------*\