Setting up a autoconf configure system

[Ian Lance Taylor]

On Mon, Mar 4, 2013 at 4:09 PM, Michael Powell <mwpowellhtx@gmail.com> wrote:
>
> I don't know if possibly the folks on this list have any knowledge of
> autoconf configure?

There is a mailing list for autoconf that would probably be a more
useful place to ask.
http://www.gnu.org/software/autoconf/#mailinglists

> Specifically, I have a system I'd like to build in either x86 default
> Linux GCC environment, or ARM cross compiler.
>
> I want to specify "./configure --target" (usage?) and when x86 or ARM
> (or some derived Makefile variables) is detected, include the
> appropriate $(TARGET_OS).make file.

In autoconf terminology this is not a target.  It is a host.

> The docs on config.sub and config.guess are rather fuzzy. The examples
> I am digging up are vastly more complex than we need.

I wrote an introduction a long time ago at
http://www.airs.com/ian/configure/ .  It may help; not sure.

Basically you want something like

AC_CANONICAL_SYSTEM
case "${host}" in
  *86*) HOST_OS=x86 ;;
  *arm*) HOST_OS=arm ;;
  *) AC_ERROR([huh])
esac
AC_SUBST(HOST_OS)

and then in your Makefile

include $(HOST_OS).make

Ian