buildd path name length

[Florian Weimer <fw@deneb.enyo.de>]

Suppose that a package wants to create a UNIX domain socket as part of
its test suite.  If the socket is created within the package build
directory, this might fail because of the quite low path name length
limit.  What is the correct way of dealing with this?  "mktemp -d" uses
TMPDIR, which is potentially affected by the same issue.

(My personal opinion is "fix the buildd", especially since none of the
official buildds seems to use long path names, but there is
disagreement.)