configure.ac: add -Werror to default compiler options

[Octavian Voicu]

On Thu, Sep 1, 2011 at 4:27 AM, Dan Kegel <dank at kegel.com> wrote:
> At which point it would probably be a fine idea to add -Werror by default;
> buildbot will help keep everyone in sync, even if they're using a compiler
> that doesn't catch as many warnings as the one buildbot uses.

Have you tried compiling on 64-bit? There are still a handful of
compile warnings there (most in oleaut32/tmarshal.c; then
setupapi/devinst.c; dsound+winmm).

Octavian