xaw_use_xprint and XAW_CHECK_XPRINT_SUPPORT auto detected

[Jeremy C. Reed]

lib/libXaw/xaw.m4 provides:

  "If neither --enable-xprint nor --disable-xprint are given, the presence 
  of an Xaw with Xprint support will be auto detected."

Is that auto-detection necessary?

It makes inconsistent builds of xman and xlogo for example. Those are the 
two I have learned problems about, but now I see many apps use it.

If it detects, then it adds additional dependencies: xprintutil and xp.

I think that it should be enabled or disabled but not auto-detected.

What are other packagers doing for this -- explicitely defining 
--disable-xprint?

As for "auto-detection" of features -- what other examples does Xorg have 
of this -- and when is it acceptable and not acceptable?

  Jeremy C. Reed