Why run the windres test on Linux?

[DJ Delorie]

> If it isn't easy to make the tests self-contained,

It isn't easy to make *useful* tests self-contained.  Practical RC
files rely heavily on <windows.h>, so if we want people to contribute
test cases (based on past history of windres bugs, we do) we need to
make it easy for them to produce them, and easy to maintain wrt win32
API changes.

However, I've not a strong opinion about this.

> Or just not building windres by default on targets other than
> Windows.

They're not built by default.  They're only built if you use
--with-windres (a future patch will add this) or --enable-targets=all.
A plain old native Linux build should not build windres.