Re: Possible bug: AC_USE_SYSTEM_EXTENSIONS ignores "AS_IF" conditionals

[David A. Wheeler]

On Mon, 22 Sep 2014 08:51:52 -0600, Eric Blake <address@hidden> wrote:
> I don't think what you are asking for is possible.  Either you want to
> use extensions (and just use the macro) or you don't.  I don't really
> see a use case for wanting extensions on only some of the builds.

I want to write code that will *use* extensions where available, but will 
portably run on
systems that don't have the extensions.  Various parts need to detect the
presence of some extensions, and then provide alternatives when they're
not available.  Of course, that means I need to able to *test* the alternatives.

Thus, I want to be able to easily *disable*
extensions & then see if the code compiles/links/runs correctly.
My intent was to add a simple configure flag to disable extensions, to enable
some basic testing in those cases.

--- David A. Wheeler