[3.15] gh-154389: Do not use uuid_create() on OpenBSD (GH-154390) (GH-154391)

Like NetBSD, OpenBSD generates version 4 UUIDs in uuid_create(), so it
cannot be used for uuid.uuid1().
(cherry picked from commit c76fb91)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: 3 people

Misc/NEWS.d/next/Library/2026-07-21-20-34-05.gh-issue-154389.DlTiii.rst

@@ -0,0 +1,3 @@
+Fix :func:`uuid.uuid1` on OpenBSD:
+it returned a version 4 UUID,
+because ``uuid_create()`` generates random UUIDs on this platform.

configure

@@ -4003,9 +4003,10 @@ AS_VAR_IF([ac_cv_have_uuid_generate_time_safe], [yes], [
   AC_DEFINE([HAVE_UUID_GENERATE_TIME_SAFE], [1])
 ])
 
-# gh-124228: While the libuuid library is available on NetBSD, it supports only UUID version 4.
+# gh-124228: While the libuuid library is available on NetBSD and OpenBSD,
+# it supports only UUID version 4.
 # This restriction inhibits the proper generation of time-based UUIDs.
-if test "$ac_sys_system" = "NetBSD"; then
+if test "$ac_sys_system" = "NetBSD" || test "$ac_sys_system" = "OpenBSD"; then
   have_uuid=missing
   AC_DEFINE([HAVE_UUID_H], [0])
 fi