blkid: fix blkid time diff bug

When calculating time diffs, use difftime() instead of risking
integer overflow.  Also build a "blkid" binary.

Addresses-Google-Bug: #11175082
Change-Id: I23521f45204574bb32f152926401c2cbad93175b

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed