The build-depends field has been moved from the package level to the individual library and executable components. (And the new build-tools and pkgconfig-depends fields are similarly attached to components.) I'm not sure whether this is a good idea, but more specifically I came across this in the parser for old-style package descriptions in Distribution.PackageDescription: -- The 'build-depends' field was global so far. Now it's -- supported in each section. -- XXX: we actially have two options here -- (1) put all dependencies into the library section, if the -- library section would be empty, mark it as not buildable -- (2) duplicate all dependencies in each section, libraries -- and executables -- Right now we go with (1) Surely (1) is just wrong. Is there any reason not to do (2)?