Cross-compilation (was: Thank you for not using autoconf)

[Rich Felker]

On Tue, Jun 04, 2013 at 10:56:25AM +0200, Laurent Bercot wrote:
> > Autotools-based can be good or bad for cross-compiling. The biggest
> > issue is that lots of people write broken tests that need to run test
> > programs to get the results they want.
> 
>  As long as there are differences between systems, build-time tests
> will be necessary to check for what the system provides and what
> needs working around.

I think you misread what I wrote. The problem is needing to _run_ the
test program. Proper autoconf tests simply test preprocessing,
compiling, or linking, but not running the resulting executable. It's
rare that you need to run a test program, and when you do, it's often
a bug for other reasons. For instance you might test for a buggy
version of some syscall, and find that it's working, but then get the
buggy one at application-runtime when somebody runs your binary on an
older kernel.

So, basically what I'm saying is that if you need to probe _behavior_
of an interface, that probing should be in your application itself,
and it should be done when the application is run, rather than being
part of the application's configure process.

Rich