pristine-tar in maverick needs to know about TAR_LONGLINK_100 as understood by the new tar version

Binary package hint: pristine-tar

Hiya,

pristine-tar won't work so well with the new tar in Maverick; xdelta failures abound, unless the tarball happens to be one of the ones fixed by said update.

It needs to be updated to understand the TAR_LONGLINK_100 envrionment variable that tar now takes advantage of. This debdiff (and upload) backports the changes from upstream to try the new behaviour first and then ask tar to make use of the old one if this fails.

Test case (ensure you are getting tar from -proposed)

(previously broken tarball)

1. sudo apt-get install tar pristine-tar git
2. git clone git://github.com/iainlane/f-spot.git
3. git branch --track pristine-tar origin/pristine-tar
4. pristine-tar checkout f-spot_0.8.2.orig.tar.gz
<STILL NO ERROR>

(previously working tarball)

1. sudo apt-get install tar pristine-tar git devscripts
2. debcheckout banshee
3. git branch --track pristine-tar origin/pristine-tar
4. pristine-tar checkout banshee_1.9.2.orig.tar.gz
<error>
5. <install new pristine-tar>
6. pristine-tar checkout banshee_1.9.2.orig.tar.gz
<xdelta failure, but then on the retry with TAR_LONGLINK_100, success>

Regression potential

These two updates are designed to go together. Essentially this patch modifies pristine-tar to call tar a second time with an environment variable set if the first invocation fails. Thus the only regression could come from tar itself.