[glibc] posix: Fix test-errno build with fortify enable

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=df43ea489ce492ccf9c787054ca2bb11ddf31b27

commit df43ea489ce492ccf9c787054ca2bb11ddf31b27
Author: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Date:   Mon Jul 24 16:38:17 2023 -0300

    posix: Fix test-errno build with fortify enable
    
    With gcc 11.3.1, building with -D_FORTIFY_SOURCE=2 shows:
    
    In function ‘getgroups’,
        inlined from ‘do_test’ at test-errno.c:129:12:
    ../misc/sys/cdefs.h:195:6: error: argument 1 value -1 is negative
    [-Werror=stringop-overflow=]
      195 |    ? __ ## f ## _alias (__VA_ARGS__)
          \
          |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ../posix/bits/unistd.h:115:10: note: in expansion of macro
    ‘__glibc_fortify’
      115 |   return __glibc_fortify (getgroups, __size, sizeof (__gid_t),
          |          ^~~~~~~~~~~~~~~
    ../posix/bits/unistd.h: In function ‘do_test’:
    ../posix/bits/unistd-decl.h:135:28: note: in a call to function
    ‘__getgroups_alias’ declared with attribute ‘access (write_only, 2, 1)’
      135 | extern int __REDIRECT_NTH (__getgroups_alias, (int __size,
          __gid_t __list[]),
          |                            ^~~~~~~~~~~~~~~~~
    ../misc/sys/cdefs.h:264:6: note: in definition of macro ‘__REDIRECT_NTH’
      264 |      name proto __asm__ (__ASMNAME (#alias)) __THROW
    
    It builds fine with gcc 12 and gcc 13.
    
    Checked on x86_64-linux-gnu.
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Diff:
---
 posix/test-errno.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/posix/test-errno.c b/posix/test-errno.c
index 305bc42938..3685fd1555 100644
--- a/posix/test-errno.c
+++ b/posix/test-errno.c
@@ -17,6 +17,13 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <sys/cdefs.h>
+#include <libc-diag.h>
+#if __GNUC_PREREQ (7, 0)
+/* Triggered by getgroup fortify wrapper.  */
+DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow");
+#endif
+
 #include <errno.h>
 #include <limits.h>
 #include <grp.h>
@@ -34,7 +41,6 @@
 #include <sys/uio.h>
 #include <unistd.h>
 #include <netinet/in.h>
-#include <libc-diag.h>
 
 /* This is not an exhaustive test: only system calls that can be
    persuaded to fail with a consistent error code and no side effects