Add TODO item for prompt -E.
Merge branch 'develop'
Add stdarg.h include wherever str.h is used.
Add strlcat to source code since Linux doesn't ship with it.
Add strlcat to the regress tests.
Add '-E' option to 'prompt' mode.
Remove 'add' from TODO.
Add an implementation of rm_overwrite() from OpenBSD.

This is not hooked up to anything yet, it might not even compile on
Linux yet.