ref: 0c7e1a950c7066b338c162fc8d302eaefa6da686
dir: /nestegg/m4/as-ac-expand.m4/
dnl as-ac-expand.m4 0.2.0
dnl autostars m4 macro for expanding directories using configure's prefix
dnl thomas@apestaart.org
dnl AS_AC_EXPAND(VAR, CONFIGURE_VAR)
dnl example
dnl AS_AC_EXPAND(SYSCONFDIR, $sysconfdir)
dnl will set SYSCONFDIR to /usr/local/etc if prefix=/usr/local
AC_DEFUN([AS_AC_EXPAND],
[
EXP_VAR=[$1]
FROM_VAR=[$2]
dnl first expand prefix and exec_prefix if necessary
prefix_save=$prefix
exec_prefix_save=$exec_prefix
dnl if no prefix given, then use /usr/local, the default prefix
if test "x$prefix" = "xNONE"; then
prefix="$ac_default_prefix"
fi
dnl if no exec_prefix given, then use prefix
if test "x$exec_prefix" = "xNONE"; then
exec_prefix=$prefix
fi
full_var="$FROM_VAR"
dnl loop until it doesn't change anymore
while true; do
new_full_var="`eval echo $full_var`"
if test "x$new_full_var" = "x$full_var"; then break; fi
full_var=$new_full_var
done
dnl clean up
full_var=$new_full_var
AC_SUBST([$1], "$full_var")
dnl restore prefix and exec_prefix
prefix=$prefix_save
exec_prefix=$exec_prefix_save
])