// allow the I/O-intensive phases of 'go list' to overlap) instead of scaling
// all the way up to GOMAXPROCS.
var listSem = make(chan semToken, 2)

type semToken struct{}

// loadImports populates w with information about the packages in the standard
// library and the packages they themselves import in w's build context.
//
// The source import path and expanded import path are identical except for vendored packages.
// For example, on return: