OpenBSD (tested 6.5 on amd64) seems to follow the same semantics
as FreeBSD for S_ISGID, even if config.mak.uname in git.git
doesn't say so.
my $all_mask = 07777;
my $dir_mask = 02770;
-# FreeBSD does not allow non-root users to set S_ISGID, so
-# git doesn't set it, either (see DIR_HAS_BSD_GROUP_SEMANTICS in git.git)
-if ($^O =~ /freebsd/i) {
+# FreeBSD and apparently OpenBSD does not allow non-root users to set S_ISGID,
+# so git doesn't set it, either (see DIR_HAS_BSD_GROUP_SEMANTICS in git.git)
+if ($^O =~ /(?:free|open)bsd/i) {
$all_mask = 0777;
$dir_mask = 0770;
}