dnl CF_UNION_WAIT version: 5 updated: 1997/11/23 14:49:44
dnl -------------
dnl Check to see if the BSD-style union wait is declared.  Some platforms may
dnl use this, though it is deprecated in favor of the 'int' type in Posix.
dnl Some vendors provide a bogus implementation that declares union wait, but
dnl uses the 'int' type instead; we try to spot these by checking for the
dnl associated macros.
dnl
dnl Ahem.  Some implementers cast the status value to an int*, as an attempt to
dnl use the macros for either union wait or int.  So we do a check compile to
dnl see if the macros are defined and apply to an int.
dnl
dnl Sets: $cf_cv_type_unionwait
dnl Defines: HAVE_TYPE_UNIONWAIT
AC_DEFUN([CF_UNION_WAIT],
[
AC_REQUIRE([CF_WAIT_HEADERS])
AC_MSG_CHECKING([for union wait])
AC_CACHE_VAL(cf_cv_type_unionwait,[
	AC_TRY_LINK($cf_wait_headers,
	[int x;
	 int y = WEXITSTATUS(x);
	 int z = WTERMSIG(x);
	 wait(&x);
	],
	[cf_cv_type_unionwait=no
	 echo compiles ok w/o union wait 1>&AC_FD_CC
	],[
	AC_TRY_LINK($cf_wait_headers,
	[union wait x;
#ifdef WEXITSTATUS
	 int y = WEXITSTATUS(x);
#endif
#ifdef WTERMSIG
	 int z = WTERMSIG(x);
#endif
	 wait(&x);
	],
	[cf_cv_type_unionwait=yes
	 echo compiles ok with union wait and possibly macros too 1>&AC_FD_CC
	],
	[cf_cv_type_unionwait=no])])])
AC_MSG_RESULT($cf_cv_type_unionwait)
test $cf_cv_type_unionwait = yes && AC_DEFINE(HAVE_TYPE_UNIONWAIT)
])dnl
