argument, AUTOCONF-FLAGS.
* tests/mktests.sh (update_exclude_list): Add
AC_SYS_RESTARTABLE_SYSCALLS and AC_FUNC_WAIT3.
* tests/semantics.at: Test AC_SYS_RESTARTABLE_SYSCALLS and
AC_FUNC_WAIT3 with "-W no-obsolete".
(_AC_FUNC_VFORK): this.
Remove AC_DEFINEs and don't guess cross-compilation values.
(_AC_FUNC_FORK): New, check whether fork() isn't just a stub.
(AC_FUNC_FORK): New, use _AC_FUNC_VFORK and _AC_FUNC_FORK to
define HAVE_WORKING_FORK, HAVE_WORKING_VFORK; and vfork to fork if
vfork doesn't work.
Guess values if cross-compiling, but warn.
* acfunctions: Add AC_FUNC_FORK.
* doc/autoconf.texi: Document AC_FUNC_FORK. Give example to define
and vfork appropriately.
