patch applied (cabal): PackageDescription.hs: add check for existence of license file

Sat Jan 26 19:10:33 PST 2008 Brent Yorgey * PackageDescription.hs: add check for existence of license file Added a check for the existence of the license file (if one is specified in a license-file: field) during description file sanity checking. If a license is specified but does not exist, a warning is generated. This patch resolves issue #180. M ./Distribution/PackageDescription.hs -4 +18