Issue #7333: The `posix` module gains an `initgroups()` function providing
access to the initgroups(3) C library call on Unix systems which implement
it.  Patch by Jean-Paul Calderone.
diff --git a/configure.in b/configure.in
index 95d100a..e7e6b91 100644
--- a/configure.in
+++ b/configure.in
@@ -2547,7 +2547,7 @@
  clock confstr ctermid execv fchmod fchown fork fpathconf ftime ftruncate \
  gai_strerror getgroups getlogin getloadavg getpeername getpgid getpid \
  getpriority getresuid getresgid getpwent getspnam getspent getsid getwd \
- kill killpg lchmod lchown lstat mkfifo mknod mktime \
+ initgroups kill killpg lchmod lchown lstat mkfifo mknod mktime \
  mremap nice pathconf pause plock poll pthread_init \
  putenv readlink realpath \
  select sem_open sem_timedwait sem_getvalue sem_unlink setegid seteuid \