Bug#855464: devscripts: [mk-origtargz] Fails to create tar if too many files excluded

[Jeremy Bicha]

Package: devscripts
Version: 2.16.8

I am working on packaging mozjs38, a requirement for gnome-shell 3.24.

mozjs is the JavaScript engine of Firefox. The only official "release"
tarball was 38.2. Fedora has instead used the regular Firefox 38.8 ESR
tarball (so that 8 months of security and other bugfixes are
included). The Firefox tarball works but contains a lot of unused
files. Working with such a massive tarball is painful and unnecessary
in the case so I looked to using uscan with Files-Excluded in
debian/copyright.

However, mk-origtargz is apparently not designed to handle this level
of pruning.

Test Case
--------------
Clone this repo:
https://anonscm.debian.org/git/users/jbicha-guest/mk-origtargz-test
cd mk-origtargz-test
uscan -dd --verbose

Result
---------
uscan info: Executing internal command:
   mk-origtargz --package mozjs38 --version 38.8.0 --compression gzip
--directory ../tarballs --copyright-file debian/copyright
../tarballs/firefox-38.8.0esr.source.tar.bz2
Can't exec "tar": Argument list too long at
/usr/share/perl5/Dpkg/IPC.pm line 308.

More Info
-------------
I was able to trigger this failures with just 4 lines in
Files-Excluded (but those directories contain thousands of files)
Files-Excluded:
 browser
 dom
 media
 security

I am reporting this from Ubuntu zesty which uses 2.16.8ubuntu1, but
the changelog doesn't look like anything relevant has changed in the
current sid version.

Thanks,
Jeremy Bicha