fixes to parser from krasimir, fixes to sdist from ross
Krasimir says: Small fixes in the parser/printer. When there is a package description with executables only then the old implementation of pretty printer was written to print empty "exposed-modules" field while there isn`t any library. After that the parser will generate PackageDescription with (Just emptyLibrary) instead of Nothing. Now exposed-modules field is printed only if library /= Nothing Ross says: In smartCopySources, don't try to strip the prefix if it was ".", because joinFileName "." x == x (fixes bug reported by Iavor Diatchki) Improve sdist a bit: copy files named in main-is, license-file and c-sources. Also supply a default Setup.hs if none is present. This will get it working for only the simplest of packages. It omits header files, configure stuff and files named in the buildinfo file. To do it properly, we'd need a field in the package description listing extra files to copy into a source distribution.