hurd: whitelist rtld symbols expected to be overridable

* sysdeps/mach/hurd/localplt.data: New file.

ChangeLog

@@ -346,6 +346,8 @@
 	__clock_gettime and __nanosleep instead of clock_gettime and
 	nanosleep.
 
+	* sysdeps/mach/hurd/localplt.data: New file.
+
 2018-04-02  Agustina Arzille  <avarzille@riseup.net>
             Amos Jeffries  <squid3@treenet.co.nz>
             David Michael  <fedora.dm0@gmail.com>

sysdeps/mach/hurd/localplt.data

@@ -0,0 +1,20 @@
+# The dynamic linker has its own versions of basic functions for initial loading
+# of shared libraries.  These need to be overriden by libc once loaded.
+ld.so: __open
+ld.so: __close
+ld.so: __libc_read
+ld.so: __libc_write
+ld.so: __writev
+ld.so: __libc_lseek64
+ld.so: __map
+ld.so: __fxstat64
+ld.so: __xstat64
+ld.so: __access
+ld.so: __access_noerrno
+ld.so: __getpid
+ld.so: __getcwd
+ld.so: __sbrk
+ld.so: __strtoul_internal
+ld.so: _exit
+ld.so: abort
+ld.so: _hurd_intr_rpc_mach_msg