bug#23341: x-show-tip does not respect the value of tooltip-hide-delay, and the default tooltip timeout isn't configurable

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: clement.pitclaudel@live.com,  23341@debbugs.gnu.org
> Date: Sat, 30 Apr 2022 17:38:45 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > It looks like you did that only for X?  What about the other 4
> > implementations of this function? is the divergence in behavior
> > intended?
> 
> Nope -- fixed now.

Err... it doesn't compile here:

    CC       w32fns.o
  w32fns.c: In function 'Fx_show_tip':
  w32fns.c:7369:15: error: 'Vx_show_tooltip_timeout' undeclared (first use in 
this function)
   7369 |     timeout = Vx_show_tooltip_timeout;
        |               ^~~~~~~~~~~~~~~~~~~~~~~
  w32fns.c:7369:15: note: each undeclared identifier is reported only once for 
each function it appears in
  Makefile:421: recipe for target `w32fns.o' failed

I think the variable should be moved to a common file, perhaps
dispnew.c?

Also, nsterm.m should be modified as well, no?