remove superfluous libc_hidden_proto(memcpy) and #include

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

libc/sysdeps/linux/common/__rt_sigtimedwait.c

@@ -12,11 +12,7 @@
 #include <signal.h>
 #include <string.h>
 
-libc_hidden_proto(memcpy)
-
 #ifdef __NR_rt_sigtimedwait
-#include <string.h>
-libc_hidden_proto(memcpy)
 
 # ifdef __UCLIBC_HAS_THREADS_NATIVE__
 #  include <sysdep-cancel.h>

libc/sysdeps/linux/common/__rt_sigwaitinfo.c

@@ -12,12 +12,8 @@
 #include <signal.h>
 #include <string.h>
 
-libc_hidden_proto(memcpy)
-
 #ifdef __NR_rt_sigtimedwait
 
-#include <string.h>
-
 # ifdef __UCLIBC_HAS_THREADS_NATIVE__
 #  include <sysdep-cancel.h>