Implement file(1).

Unlike the POSIX file(1), there's no magic file here, just hard-coded
common (non-obsolete) file formats. Personally most of my use of file(1)
is as a one-line readelf(1) summarizer, so although I assume a full POSIX
file(1) is out of scope (because just the database would likely be larger
than all the rest of toybox), a subset that only supports in-use file types
actually covers most of the use cases I encounter personally.

Also fix peek_be/peek_le.
2 files changed