errno: hide __libc_resp, __libc_errno, and __libc_h_errno

Signed-off-by: Khem Raj <raj.khem@gmail.com>

libc/inet/resolv.c

@@ -3018,7 +3018,7 @@ __thread struct __res_state *__resp = &_res;
  *        relocations.
  */
 extern __thread struct __res_state *__libc_resp
-       __attribute__ ((alias ("__resp")));
+       __attribute__ ((alias ("__resp"))) attribute_hidden;
 # else
 #  undef __resp
 struct __res_state *__resp = &_res;

libc/misc/internals/errno.c

@@ -4,15 +4,14 @@
 __thread int errno;
 __thread int h_errno;
 
-extern __thread int __libc_errno __attribute__ ((alias ("errno")));
-extern __thread int __libc_h_errno __attribute__ ((alias ("h_errno")));
+extern __thread int __libc_errno __attribute__ ((alias ("errno"))) attribute_hidden;
+extern __thread int __libc_h_errno __attribute__ ((alias ("h_errno"))) attribute_hidden;
 #define h_errno __libc_h_errno
 
 #else
 #include "internal_errno.h"
 int errno = 0;
 int h_errno = 0;
-
 #ifdef __UCLIBC_HAS_THREADS__
 libc_hidden_def(errno)
 weak_alias(errno, _errno)