rdmd makes too many stat() calls, of which many are not traced #409

Transferred from: https://issues.dlang.org/show_bug.cgi?id=11827

User @andralex reported (2013-Dec-26 12:08:04):

#64 introduces this. Basically calls like exists("filename") and isDir("filename") make one stat call each, whereas calling stat once offers all information. The extra calls are not recorded with yap() either.

Excessive stat() calls are a major scalability issue.

Arguably the best fix would be to offer a nice API as noted in the pull request.