Relative pathes in ipkg (e.g. sourcedir) should be treated realtive to the ipkg-file (and not the current working directory)

[alaendle]

Otherwise we assume that the idris compiler is called from a specific working directory - normally the directory where the ipkg file resides; but is this limitation necessary or useful?

I would suggest that the compiler treats relative paths in the package file realtive to the location of the package file; which makes more sense, since the behaviour/outcome would be deterministic.