add hidden proto for memset as pointed out by Peter S. Mazinger

libc/sysdeps/linux/common/sigqueue.c

@@ -25,6 +25,7 @@
 
 libc_hidden_proto(getpid)
 libc_hidden_proto(getuid)
+libc_hidden_proto(memset)
 
 #ifdef __NR_rt_sigqueueinfo