Mark internal unistd functions hidden in ld.so

Since internal unistd functions are only used internally in ld.so and
libc.so, they can be made hidden.  __close, __getcwd, __getpid,
__libc_read and __libc_write can't be hidden in ld.so on Hurd since they
will be preempted by the ones in libc.so after bootstrap.

	[BZ #19122]
	* include/unistd.h [IS_IN (rtld)]: Include <dl-unistd.h>.
	* sysdeps/generic/dl-unistd.h: New file.
	* sysdeps/mach/hurd/dl-unistd.h: Likewise.

ChangeLog

@@ -1,3 +1,10 @@
+2016-01-05  H.J. Lu  <hongjiu.lu@intel.com>
+
+	[BZ #19122]
+	* include/unistd.h [IS_IN (rtld)]: Include <dl-unistd.h>.
+	* sysdeps/generic/dl-unistd.h: New file.
+	* sysdeps/mach/hurd/dl-unistd.h: Likewise.
+
 2016-01-05  H.J. Lu  <hongjiu.lu@intel.com>
 
 	 [BZ #19122]

include/unistd.h

@@ -158,7 +158,7 @@ rtld_hidden_proto (__libc_enable_secure)
 
 
 /* Various internal function.  */
-extern void __libc_check_standard_fds (void);
+extern void __libc_check_standard_fds (void) attribute_hidden;
 
 
 /* Internal name for fork function.  */
@@ -176,6 +176,10 @@ extern int __have_dup3 attribute_hidden;
 extern int __getlogin_r_loginuid (char *name, size_t namesize)
      attribute_hidden;
 
+#  if IS_IN (rtld)
+#   include <dl-unistd.h>
+#  endif
+
 __END_DECLS
 # endif
 

sysdeps/generic/dl-unistd.h

@@ -0,0 +1,30 @@
+/* Functions with hidden attribute internal to ld.so, which are declared
+   in include/unistd.h.  Generic version.
+   Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+extern __typeof (__access) __access attribute_hidden;
+extern __typeof (__brk) __brk attribute_hidden;
+extern __typeof (__close) __close attribute_hidden;
+extern __typeof (__getcwd) __getcwd attribute_hidden;
+extern __typeof (__getpid) __getpid attribute_hidden;
+extern __typeof (__libc_read) __libc_read attribute_hidden;
+extern __typeof (__libc_write) __libc_write attribute_hidden;
+extern __typeof (__lseek) __lseek attribute_hidden;
+extern __typeof (__profil) __profil attribute_hidden;
+extern __typeof (__read) __read attribute_hidden;
+extern __typeof (__sbrk) __sbrk attribute_hidden;

sysdeps/mach/hurd/dl-unistd.h

@@ -0,0 +1,28 @@
+/* Functions with hidden attribute internal to ld.so, which are declared
+   in include/unistd.h.  Hurd version.
+   Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* __close, __getcwd, __getpid, __libc_read and __libc_write can't be
+   hidden in ld.so on Hurd since they will be preempted by the ones in
+   libc.so after bootstrap.  */
+extern __typeof (__access) __access attribute_hidden;
+extern __typeof (__brk) __brk attribute_hidden;
+extern __typeof (__lseek) __lseek attribute_hidden;
+extern __typeof (__profil) __profil attribute_hidden;
+extern __typeof (__read) __read attribute_hidden;
+extern __typeof (__sbrk) __sbrk attribute_hidden;