id: handle systems without getgroups support

If getgroups failed with ENOSYS, mgetgroups would unnecessarily
fail, and that provoked id into freeing an uninitialized pointer.
Meanwhile, we were not using xalloc_die properly.  Both issues
are better solved in gnulib, by introducing xgetgroups; this
patch uses the new interface.

Regression introduced by commit 6a31fd8d7.

* gnulib: Update, for mgetgroups improvments.
* src/id.c (print_full_info): Adjust caller to die on allocation
failure, and no longer worry about ENOSYS.
* src/group-list.c (print_group_list): Likewise.
* src/setuidgid.c (main): Likewise.
* NEWS: Mention the fix.
* THANKS: Update.
Reported by Scott Harrison.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/id.c b/src/id.c
index 9a00f5ce4..96d8e965e 100644
--- a/src/id.c
+++ b/src/id.c
@@ -296,9 +296,9 @@ print_full_info (const char *username)
     gid_t *groups;
     int i;
 
-    int n_groups = mgetgroups (username, (pwd ? pwd->pw_gid : (gid_t) -1),
+    int n_groups = xgetgroups (username, (pwd ? pwd->pw_gid : (gid_t) -1),
                                &groups);
-    if (n_groups < 0 && errno != ENOSYS)
+    if (n_groups < 0)
       {
         if (username)
           {