compiler warnings

[Brian J. Tarricone]

Hey all,

Was perusing Planet GNOME today, and came upon this excellent post:
http://blogs.gnome.org/otte/2008/12/22/warning-options/

I'm considering adding most (maybe all) of those warning options to
xfce4-dev-tools, activated when --enable-debug=yes or
--enable-debug=full is specified.  They seem pretty damned useful, and
I know some of those would have saved me some time tracking down stupid
bugs.

They'll of course be added in such a way that they'll only be used if
the compiler supports them.

Note that this will probably introduce quite a few build failures on
any app that uses xfce4-dev-tools if -Werror is supplied to gcc (which
is what --enable-debug=full does).  In the long run, though, I think
it's better to try to fix questionable code, and devs who don't care
(hopefully no one), or users who just want to get the code compiled,
can just do --enable-debug=yes or just leave the option out entirely
and have the same behavior as now.

Any objections?  (This'll go into trunk after we branch for 4.6, not
before.)

	-brian