[Wine] How can I detect WINE from my program?

[Gert van den Berg]

An official way to detect Wine might really be handy, not just to work
around bugs, but to enable additional / different functionality when
the app is running under Wine, such as native file dialogs (not sure
if it is possible with a native Windows program?).

It must be optional and disabled by default though... (An extra
Windows version is probably the most elegant way).It must also be
possible to enable it on a per-application basis. (Like Windows
versions)

It would be really nice if it is possible to compile a single
application that run on both Windows and Wine and has native dialogs
on both. (Almost like Java, but without the overhead)

Gert