Make Multi Mount Protection (MMP) optional at configure time.

Add --{en,dis}able-mmp options for configure, default to enabled.
Also make tools fail gracefully in the event of encoutering a filesystem
with MMP enabled when the tools were compiled with --disable-mmp

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
7 files changed