Make the "cleanfile" and "cleanpatch" script warn about long lines,
by default lines whose visual width exceeds 79 characters.

Per suggestion from Auke Kok.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

This script cleans up various classes of stealth whitespace.  In
particular, it cleans up:

- Whitespace (spaces or tabs)before newline;
- DOS line endings (CR before LF);
- Space before tab (spaces are deleted or converted to tabs);
- Empty lines at end of file.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>