Re: RFE: configure -> dependency list on exit.

[Paul Eggert]

Dan Manthey <address@hidden> writes:

> AS_PACKAGE_SUGGEST([flex 2.5.x],[http://gnu.org/whereever_flex_is.html])

OK, but what is the practical difference between that, and something
like this?

AC_MSG_FAILURE([you need a suitable implementation of "lex" to build
  this package.  We suggest the latest stable version of flex
  <http://www.gnu.org/software/flex/>.])

Or, you can do something like this if you want "configure" to continue
after the warning:

AC_MSG_WARN([you lack a suitable implementation of "lex", so you won't
   be able to build this program reliably if you modify .l files.])

Or, if you want to warn at the end, you can do this:

my_warning='you lack a suitable implementation of "lex", so you won't
   be able to build this program reliably if you modify .l files.'

and then append something like this to your configure.ac file:

case $my_warning in
?*) AC_MSG_WARN("$my_warning");;
esac

An advantage of this sort of approach is that one can experiment with
these ideas now, to accomplish something in this area.  That is, one
can implement them with one's own macros; they don't require any
changes to Autoconf.  Later, if the ideas work well in practice, we
can think about how to add Autoconf macros for them (perhaps simply by
incorporating the experimental macros).