tar: Improve LFS support on 32 bit systems (#2582)

tar: Improve LFS support on 32 bit systems (#2582)

The size_t data type is only 32 bit on 32 bit sytems while off_t is
generally 64 bit to support files larger than 2 GB.

If an entry is declared to be larger than 4 GB and the entry shall be
skipped, then 32 bit systems truncate the requested amount of bytes.
This leads to different interpretation of data in tar files compared to
64 bit systems.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>