Use Cairo for wxGraphicsContext in wxX11.

Use Cairo for wxGraphicsContext in wxX11.

Check for Cairo in configure for wxX11 too.

Fix compilation of wxCairoContext for non-{GTK,MSW} platforms.

Also make wxUSE_CAIRO a "normal" option, i.e. add it to all wx/setup.h files
instead of defining it as 1 unconditionally for wxGTK and 0 for everything
else.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66094 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775