Move lock_file/unlock_file to wait.h and penn_perror to log.h.

No reason for these to live in externs.h either. Doing so lets us
completely remove the externs.h dependency from several files as well.

git-svn-id: https://pennmush.googlecode.com/svn/trunk@1783 ba372814-4f39-11de-9ad6-1127a62b9fcd