[Boost-build] What controls the error messages from "check-target-builds"?

Subject: [Boost-build] What controls the error messages from "check-target-builds"?
From: John Maddock (boost.regex_at_[hidden])
Date: 2010-07-30 11:54:29

What - if anything - controls the error messages that may be produced from 
the compiler when the "check-target-builds" rule is invoked?

Sometimes all I see is the Boost.Build messages indicating it's doing a 
configuration check, and sometimes (but not always) prior to that I see the 
compiler error messages as well.  Is there a way to control this?  I guess 
normally users would want any compiler error messages suppressed when 
building Boost (there's a message on the Boost-users group about this, and 
Boost.Regex which is why I'm asking).  Other times I want to see the errors 
so I can figure out what the configure tests are actually doing.

Ideas?

Thanks, John.