Add verbosityNoFlags function.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Cabal/Distribution/Verbosity.hs

@@ -30,6 +30,7 @@ module Distribution.Verbosity (
   moreVerbose, lessVerbose,
   intToVerbosity, flagToVerbosity,
   showForCabal, showForGHC,
+  verboseNoFlags,
 
   -- * Call stacks
   verboseCallSite, verboseCallStack,
@@ -181,6 +182,9 @@ verboseCallSite v = v { vFlags = Set.insert VCallSite (vFlags v) }
 verboseCallStack :: Verbosity -> Verbosity
 verboseCallStack v = v { vFlags = Set.insert VCallStack (vFlags v) }
 
+verboseNoFlags :: Verbosity -> Verbosity
+verboseNoFlags v = v { vFlags = Set.empty }
+
 -- | Test if we should output call sites when we log.
 isVerboseCallSite :: Verbosity -> Bool
 isVerboseCallSite = (Set.member VCallSite) . vFlags