diff --git a/winsup/cygwin/miscfuncs.h b/winsup/cygwin/miscfuncs.h
index 508729954..cc2293500 100644
--- a/winsup/cygwin/miscfuncs.h
+++ b/winsup/cygwin/miscfuncs.h
@@ -12,7 +12,6 @@ details. */
 #define likely(X) __builtin_expect (!!(X), 1)
 #define unlikely(X) __builtin_expect (!!(X), 0)
 
-extern "C" int getentropy (void *ptr, size_t len);
 
 int __reg1 winprio_to_nice (DWORD);
 DWORD __reg1 nice_to_winprio (int &);