[Pkg-emacsen-addons] Bug#803350: dh-elpa: Add Built-Using substvars entry

[Hilko Bengen]

Package: dh-elpa
Version: 0.0.15
Severity: normal

Dear maintainer,

my recent attempt at upgrading the the emacs24 package on my workstation
exposed a number of bugs in both "traditional" elisp and
dh-elpa-generated pacakges. #803344, #803348 are easily fixed by
rebuilding using current dh-elpa, #802963 looks like a very similar
issue.

Since dh-elpa uses templates to generate the install and remove scripts,
it would make sense to add a substvars entry

    misc:Built-Using=dh-elpa (= $VERSION)

so that the elpa-* packages can point to the used dh-elpa version using

    Built-Using: ${misc:Built-Using}

to their debian/control file. This would make it easier to have the
scripts in the elpa-* packages updated semi-automatically whenever
dh-elpa is updated.

Cheers,
-Hilko

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.2.0-1-amd64 (SMP w/6 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages dh-elpa depends on:
ii  emacs24  24.5+1-3

dh-elpa recommends no packages.

dh-elpa suggests no packages.

-- no debconf information