dnl CF_SUBST version: 4 updated: 2006/06/17 12:33:03
dnl --------
dnl	Shorthand macro for substituting things that the user may override
dnl	with an environment variable.
dnl
dnl	$1 = long/descriptive name
dnl	$2 = environment variable
dnl	$3 = default value
AC_DEFUN([CF_SUBST],
[AC_CACHE_VAL(cf_cv_subst_$2,[
AC_MSG_CHECKING(for $1 (symbol $2))
CF_SUBST_IF([-z "[$]$2"], [$2], [$3])
cf_cv_subst_$2=[$]$2
AC_MSG_RESULT([$]$2)
])
])dnl
