Although, I fail to understand why the duplication of work done in
prewin.h/postwin.h vs. presys.h/postsys.h is needed.

No need to force use of 32-bit time_t (which doesn't exist for 64-bit
Windows), just use defaults.

But as the return type is just 32 bits, it is actually not enough for
a HANDLE anyway on a 64-bit OS. But on the other hand, this method is
private and not used on Windows at all. So just make it abort() then.

To match what prewin.h/postwin.h do.

LibreOffice's deprecated ULONG is sal_uIntPtr, and thus 64 bits on
64-bit Windows, unlike Windows's ULONG which is 32 bits on both 32-
and 64-bit Windows. So we must hide ULONG, too, to avoid compilation
errors on 64-bit Windows.

Use LINKFLAGS instead of STDLIBS, as the latter comes way too late
in the link command and may result in some stray -L/usr/lib getting
before -L$KDEDIR/lib. Since KDE4 libs often tend to be installed
under /usr while KDE3 libs are often somewhere else such as /opt/kde3/lib,
this could cause using wrong libraries.

These methods were not implemented by any subclass, and the
implementations in the base class were empty. Still, the quite heavy
(especially in our multi-lingual builds) GetHelpText() mechanism was
called to get a string to pass to ShowHelpStatusText(). So just remove
all of it. See see fdo#33088 and fdo#33315.