-dnl ...If it's not, we need to #define MAILGROUP to 1 and make inc setgid.
-if test x"$nmh_cv_mailspool_world_writable" = x"no"; then
+dnl Also, check for liblockfile (as found on Debian systems)
+AC_CHECK_HEADER(lockfile.h, AC_CHECK_LIB(lockfile, lockfile_create) )
+
+dnl and whether its companion program dotlockfile is setgid
+AC_PATH_PROG(dotlockfilepath, dotlockfile, no)
+if test "$ac_cv_lib_lockfile_lockfile_create" != "no" ; then
+ if test "$ac_cv_path_dotlockfilepath" != "no" ; then
+ AC_CACHE_CHECK(whether dotlockfile is setgid, nmh_cv_dotlockfile_setgid,
+ [ if test -g "$ac_cv_path_dotlockfilepath" ; then
+ nmh_cv_dotlockfile_setgid=yes
+ else
+ nmh_cv_dotlockfile_setgid=no
+ fi])
+ fi
+fi
+
+dnl If mailspool is not world-writable and dotlockfile is not setgid,
+dnl we need to #define MAILGROUP to 1 and make inc setgid.
+if test x"$nmh_cv_mailspool_world_writable" = x"no" -a x"$nmh_cv_dotlockfile_setgid" != x"yes" ; then