For the loadable modules it makes sense to build for PE/COFF targets, link
those loadable modules with the import library for the Xorg executable, so
that symbols provided by the executable can be satisfied at link time (as
required by PE/COFF).
Since this uses the syntax of using the returned build target object from an
executable() with an implib: kwarg to link_with:, introduced in meson 0.42
and a syntax error with older meson, also update the minimum meson version
which we require in project() to that.
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
