RESEND: Enable GCOV Code Coverage

[Daniel Kegel]

Alexandre wrote:
> The changes may be small but they are ugly IMO. I don't think we need
> a configure option for that, it should be possible to simply do a
> 'make CFLAGS=xxx' with the appropriate options.

We used a configure option by analogy with --disable-debug, I guess,
and because it seems to be the standard way to do it
(a quick search shows that at least
ImageMagick, PlaylistManager,
oprofile, xfce, gstreamer,
dbus, plt-scheme, matchbox, KDE-Darwin,
lsh, and many others do it with --enable-gcov).

We'd be happy to rework it any way you like, if you think
following existing practice by using --enable-gcov is a bad idea.

We have a very small follow-on patch which adds lcov support.
lcov is a nice postprocessor for gcov that makes a pretty HTML
report for all of wine showing how well the Wine test suite
covers the code.

We also have an enhancement to lcov pending which lets you
see which lines of Wine are exercized by an application
but not by Wine's regression test suite.
- Dan