generalize Acquire::GzipIndex
rewrite compressed indexes test to check with all compressors

Git-Dch: Ignore
Merge remote-tracking branch 'donkult/feature/generalize-gzipindex' into debian/sid
Set STRIP_FROM_PATH for doxygen

Signed-off-by: Trần Ngọc Quân <vnwildman@gmail.com>
Merge branch 'debian/sid' into debian/experimental

Conflicts:
	apt-pkg/acquire-item.cc
Add missing "adduser" dependency (for the new _apt user)

Closes: #763004
Thanks: Russ Allbery
Test if TMPDIR is a directory in apt-key and if not unset it

This prevents a failure in mktemp -d - it will blindly trust
TMPDIR and not use something else if the dir is not there.
update symbols file
fix Configuration::FindVector API

Git-Dch: Ignore
mark private methods as hidden

We are the only possible users of private methods, so we are also the
only users who can potentially export them via using them in inline
methods. The point is: We don't need these symbols exported if we don't
do this, so marking them as hidden removes some methods from the API
without breaking anything as nobody could have used them.

Git-Dch: Ignore
support parsing of all hashes for pdiff

The fileformat of a pdiff index stores currently only SHA1 hashes. With
this change, we look for all other hashes we support as well and take
what we get, so that we can work after the release of jessie to get
right of SHA1 if we want to.

Note that the completely patched file is and was checked against the
hashes collected from the Release file, so this transition isn't mission
critical.
fix another instance of warning: extra ‘;’ [-Wpedantic]

Git-Dch: Ignore