[2.23 COMMITTED] Fix tst-dlsym-error build

[Florian Weimer]

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.

(cherry picked from commit e91bd7465816f474617dcb4bbfe72f3594c5783c)

2016-03-31  Adhemerval Zanella  <adhemerval.zanella@linaro.org>

	* elf/tst-dlsym-error.c: Include <string.h> for strchrnul.

diff --git a/elf/tst-dlsym-error.c b/elf/tst-dlsym-error.c
index 11b0358..fb084c5 100644
--- a/elf/tst-dlsym-error.c
+++ b/elf/tst-dlsym-error.c
@@ -20,6 +20,7 @@
 #include <gnu/lib-names.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 /* Used to disambiguate symbol names.  */
 static int counter;