Revert these two upstream commits, to unbreak ASAN:

commit e91bd7465816f474617dcb4bbfe72f3594c5783c
Author: Adhemerval Zanella <adhemerval.zanella@linaro.com>
Date:   Thu Mar 31 10:51:51 2016 -0300

    Fix tst-dlsym-error build
    
    This patch fixes the new test tst-dlsym-error build on aarch64
    (and possible other architectures as well) due missing strchrnul
    definition.
    
        * elf/tst-dlsym-error.c: Include <string.h> for strchrnul.

commit 7d45c163d00c88d5875a112343c4ea3e61349e6b
Author: Florian Weimer <fweimer@redhat.com>
Date:   Thu Mar 31 11:26:55 2016 +0200

    Report dlsym, dlvsym lookup errors using dlerror [BZ #19509]
    
        * elf/dl-lookup.c (_dl_lookup_symbol_x): Report error even if
        skip_map != NULL.
        * elf/tst-dlsym-error.c: New file.
        * elf/Makefile (tests): Add tst-dlsym-error.
        (tst-dlsym-error): Link against libdl.

Index: b/elf/Makefile
===================================================================
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -149,7 +149,7 @@ tests += loadtest restest1 preloadtest l
 	 tst-nodelete) \
 	 tst-initorder tst-initorder2 tst-relsort1 tst-null-argv \
 	 tst-ptrguard1 tst-tlsalign tst-tlsalign-extern tst-nodelete-opened \
-	 tst-nodelete2 tst-audit11 tst-audit12 tst-dlsym-error
+	 tst-nodelete2 tst-audit11 tst-audit12
 #	 reldep9
 ifeq ($(build-hardcoded-path-in-tests),yes)
 tests += tst-dlopen-aout
@@ -1258,5 +1258,3 @@ $(objpfx)tst-prelink-cmp.out: tst-prelin
 $(objpfx)tst-ldconfig-X.out : tst-ldconfig-X.sh $(objpfx)ldconfig
 	$(SHELL) $< '$(common-objpfx)' '$(test-wrapper)' '$(test-wrapper-env)' > $@; \
 	$(evaluate-test)
-
-$(objpfx)tst-dlsym-error: $(libdl)
Index: b/elf/dl-lookup.c
===================================================================
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -858,6 +858,7 @@ _dl_lookup_symbol_x (const char *undef_n
   if (__glibc_unlikely (current_value.s == NULL))
     {
       if ((*ref == NULL || ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK)
+	  && skip_map == NULL
 	  && !(GLRO(dl_debug_mask) & DL_DEBUG_UNUSED))
 	{
 	  /* We could find no value for a strong reference.  */
Index: b/elf/tst-dlsym-error.c
===================================================================
--- a/elf/tst-dlsym-error.c
+++ /dev/null
@@ -1,114 +0,0 @@
-/* Test error reporting for dlsym, dlvsym failures.
-   Copyright (C) 2016 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/>.  */
-
-#include <dlfcn.h>
-#include <gnu/lib-names.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-/* Used to disambiguate symbol names.  */
-static int counter;
-
-static void
-test_one (void *handle, const char *name, void *(func) (void *, const char *),
-          const char *suffix)
-{
-  ++counter;
-  char symbol[32];
-  snprintf (symbol, sizeof (symbol), "no_such_symbol_%d", counter);
-  char *expected_message;
-  if (asprintf (&expected_message, ": undefined symbol: %s%s",
-                symbol, suffix) < 0)
-    {
-      printf ("error: asprintf: %m\n");
-      abort ();
-    }
-
-  void *addr = func (handle, symbol);
-  if (addr != NULL)
-    {
-      printf ("error: %s: found symbol \"no_such_symbol\"\n", name);
-      abort ();
-    }
-  const char *message = dlerror ();
-  if (message == NULL)
-    {
-      printf ("error: %s: missing error message\n", name);
-      abort ();
-    }
-  const char *message_without_path = strchrnul (message, ':');
-  if (strcmp (message_without_path, expected_message) != 0)
-    {
-      printf ("error: %s: unexpected error message: %s\n", name, message);
-      abort ();
-    }
-  free (expected_message);
-
-  message = dlerror ();
-  if (message != NULL)
-    {
-      printf ("error: %s: unexpected error message: %s\n", name, message);
-      abort ();
-    }
-}
-
-static void
-test_handles (const char *name, void *(func) (void *, const char *),
-              const char *suffix)
-{
-  test_one (RTLD_DEFAULT, name, func, suffix);
-  test_one (RTLD_NEXT, name, func, suffix);
-
-  void *handle = dlopen (LIBC_SO, RTLD_LAZY);
-  if (handle == NULL)
-    {
-      printf ("error: cannot dlopen %s: %s\n", LIBC_SO, dlerror ());
-      abort ();
-    }
-  test_one (handle, name, func, suffix);
-  dlclose (handle);
-}
-
-static void *
-dlvsym_no_such_version (void *handle, const char *name)
-{
-  return dlvsym (handle, name, "NO_SUCH_VERSION");
-}
-
-static void *
-dlvsym_glibc_private (void *handle, const char *name)
-{
-  return dlvsym (handle, name, "GLIBC_PRIVATE");
-}
-
-static int
-do_test (void)
-{
-  test_handles ("dlsym", dlsym, "");
-  test_handles ("dlvsym", dlvsym_no_such_version,
-                ", version NO_SUCH_VERSION");
-  test_handles ("dlvsym", dlvsym_glibc_private,
-                ", version GLIBC_PRIVATE");
-
-  return 0;
-}
-
-
-#define TEST_FUNCTION do_test ()
-#include "../test-skeleton.c"