This port hasn't been updated for ages and is not used by anybody any
longer, so remove its code to facilitate maintenance.
Also remove references to this port from the documentation and most of
the other places (VMS-specific descrip.vms files still check for it
because it's not clear how to update them all), including configure.
Regenerate the latter and rebake all makefiles.
Finally document that this port is not available any longer.
We must always use them with wxGTK2, so don't check wxHAVE_GDK_X11 for
it, otherwise we're never going to include X11 libraries when using it,
but they are always required.
See #22813.
X11 headers and libraries are only required if we're actually using X11
which may not be the case.
This allows to build wxGTK on the systems using Wayland-only GTK.
uuid should be linked before oleacc, otherwise it causes multiple definition of `IID_IAccessible' (with MinGW64 gcc).
To simplify even more, specify all required libraries in wxTOOLKIT_LIBRARIES, in the same order as in the makefiles.
Add uxtheme library, it is required since wxUxThemeEngine wrapper has been removed.
Add CMake build system for libraries, tests and samples
update_files.py converts build/files into CMake format.
build/update-setup-h has been modified to update build/cmake/setup.h.in.
