Bump library version to libapt-pkg4.14
apt-get: Create the temporary downloaded changelog inside tmpdir

The code is creating a secure temporary directory, but then creates
the changelog alongside the tmpdir in the same base directory. This
defeats the secure tmpdir creation, making the filename predictable.

Inject a '/' between the tmpdir and the changelog filename.
[l10n] Updated Czech translation of apt

Closes: #764055
Rename DropPrivs() to DropPrivileges()

Git-Dch: ignore
Ignore EINVAL from prctl(PR_SET_NO_NEW_PRIVS)

Ignore a EINVAL error here as it means that the kernel is too old
to understand this option. We should not fail hard in this case
but just ignore the error.

closes: 764066
fix foldmarkers in fileutl.cc

Git-Dch: Ignore
set PR_SET_NO_NEW_PRIVS also if run as non-root

Changing user and co works only as root, but can do some things for
methods run as normal user as well to protect them from being able to
call setuid binaries like sudo to elevate their privileges.
Also uses a cheap trick now to build with old unsupporting kernels.