diff --git a/mingw-w64-headers/crt/intrin.h b/mingw-w64-headers/crt/intrin.h
index 198c94f..4e840fa 100644
--- a/mingw-w64-headers/crt/intrin.h
+++ b/mingw-w64-headers/crt/intrin.h
@@ -56,9 +56,6 @@
 
 #if defined(__GNUC__) && \
    (defined(__i386__) || defined(__x86_64__))
-  extern unsigned int __builtin_ia32_crc32qi (unsigned int, unsigned char);
-  extern unsigned int __builtin_ia32_crc32hi (unsigned int, unsigned short);
-  extern unsigned int __builtin_ia32_crc32si (unsigned int, unsigned int);
 #ifndef _MM_MALLOC_H_INCLUDED
 #include <stdlib.h>
 #include <errno.h>