[gcc r12-9025] libsanitizer: Avoid implicit function declaration in configure test

[Florian Weimer <fw@gcc.gnu.org>]

https://gcc.gnu.org/g:7d7146102365f708a37401c902fce2f4024b546a

commit r12-9025-g7d7146102365f708a37401c902fce2f4024b546a
Author: Florian Weimer <fweimer@redhat.com>
Date:   Wed Jan 4 11:13:17 2023 +0100

    libsanitizer: Avoid implicit function declaration in configure test
    
    libsanitizer/
    
            * configure.ac (sanitizer_supported): Include <unistd.h> for
            syscall prototype.
            * configure: Regenerate.
    
    (cherry picked from commit 6be2672e4ee41c566a9e072088cccca263bab5f7)

Diff:
---
 libsanitizer/configure    | 1 +
 libsanitizer/configure.ac | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/libsanitizer/configure b/libsanitizer/configure
index 771b135573a..ae8c1bd7e83 100755
--- a/libsanitizer/configure
+++ b/libsanitizer/configure
@@ -16028,6 +16028,7 @@ case "$target" in
     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <sys/syscall.h>
+#include <unistd.h>
 int
 main ()
 {
diff --git a/libsanitizer/configure.ac b/libsanitizer/configure.ac
index 7f1ef3979c4..ad49f29db7e 100644
--- a/libsanitizer/configure.ac
+++ b/libsanitizer/configure.ac
@@ -161,7 +161,8 @@ case "$target" in
   *-*-linux*)
     # Some old Linux distributions miss required syscalls.
     sanitizer_supported=no
-    AC_TRY_COMPILE([#include <sys/syscall.h>],[
+    AC_TRY_COMPILE([#include <sys/syscall.h>
+#include <unistd.h>],[
       syscall (__NR_gettid);
       syscall (__NR_futex);
       syscall (__NR_exit_group);