m4/as-ac-expand.m4

   1 dnl AS_AC_EXPAND(VAR, CONFIGURE_VAR)
   2 dnl example
   3 dnl AS_AC_EXPAND(SYSCONFDIR, $sysconfdir)
   4 dnl will set SYSCONFDIR to /usr/local/etc
   5
   6 AC_DEFUN([AS_AC_EXPAND],
   7 [
   8   EXP_VAR=[$1]
   9   FROM_VAR=[$2]
  10
  11   dnl first expand prefix and exec_prefix if necessary
  12   prefix_save=$prefix
  13   if test "x$prefix" = "xNONE"; then
  14     prefix=/usr/local
  15   fi
  16   exec_prefix_save=$exec_prefix
  17   if test "x$exec_prefix" = "xNONE"; then
  18     exec_prefix=/usr/local
  19   fi
  20
  21   full_var="$FROM_VAR"
  22   dnl loop until it doesn't change anymore
  23   while true; do
  24     new_full_var="`eval echo $full_var`"
  25     if test "x$new_full_var" == "x$full_var"; then break; fi
  26     full_var=$new_full_var
  27   done
  28
  29   dnl clean up
  30   full_var=$new_full_var
  31   AC_SUBST([$1], "$full_var")
  32   prefix=$prefix_save
  33   exec_prefix=$exec_prefix_save
  34 ])