* src/common.h (check_device_option): New global.

* src/common.h (check_device_option): New global.
* src/incremen.c (procdir): Use boolean and instead of bitwise
one. Patch by Jean-Louis Martineau.
Compare device numbers only if check_device_option is set.
* src/tar.c: New command line options --no-check-device and
--check-device. Proposed by Jean-Louis Martineau.
(parse_opt): Hanlde new options.
(decode_options): Initialize check_device_option to true.