It does no real harm to set it to 1 and this avoids the need for the
platform checks in setup.h files, simplifying things (although it does
require checking for GTK 3 in the code compiled for both GTK 2 and 3, as
gtkspell library can only be used with GTK 3).
The wxrc program does not depend on the GUI libraries, but only on
the base and XML libraries, so make it possible to build it in non-GUI
builds too.
Closes https://github.com/wxWidgets/wxWidgets/pull/2419
In addition to linking with Winsock 2, also use winsock2.h.
This allows to turn on IPv6 support on by default under MSW, so turn it
on under Unix too for consistency.
Predefine _WINSOCK_DEPRECATED_NO_WARNINGS to avoid warnings about
deprecated (but still available and very unlikely to be ever removed)
Winsock 1 functions that we still use.
Simplify things by putting setup.h files themselves under version
control and getting rid of setup0.h ones.
The initial motivation for using separate setup0.h files was to allow
having local changes to setup.h, but with Git there is a simple way to
do it by using "git update-index --skip-worktree include/wx/msw/setup.h"
for example, so we don't really need setup0.h any more and dropping them
makes things simpler.
