patch applied (cabal): better error messages for erroneous local C headers

[Duncan Coutts]

Thu Apr  8 19:25:43 PDT 2010  mcallister.keegan at gmail.com
  * better error messages for erroneous local C headers
  Addresses the issue in tickets #532, #648.
  When the all-together test of C libraries and headers fails, use only the
  preprocessor to probe the headers individually.  If they all check out,
  give a more equivocal error message and suggest -v3.
  

    M ./Distribution/Simple/Configure.hs -7 +21

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=cabal;a=darcs_commitdiff;h=20100409022543-b057a-4ff17da373c27f7bcd228b3b5434ed1335d3c2a2.gz