Bug#804923: FTCBFS whenever autotools-dev is more recent than apt: runs configure again without --host

[Helmut Grohne <helmut@subdivi.de>]

Source: apt
Version: 1.0.10.2
User: helmutg@debian.org
Usertags: rebootstrap

Hi Don, Julian, and Michael,

I nagged you with an unspecific "why does apt fail to cross build?" a
few times on irc, but this time you get a bug report with a diagnosis
(but no patch, sorry) for real.

The apt Debian source package takes care to create the symlinks
buildlib/config.{guess,sub} and then to run configure. At the end of
configure (via config.status), it runs "make -s dirs" which depends on
the "startup" target (buildlib/configure.mak). The startup target in
turn depends on "configure" and this is where things start to get
interesting as configure depends on buildlib/config.guess, so configure
is recreated using autoconf iff /usr/share/misc/config.guess is more
recent than configure. Now the startup target also depends on
config.status which depends on configure, so configure is run again.
Only this time no --build nor --host flags are passed. Once apt is
configured without --host, a cross build failure quickly ensues.

To verify this analysis, try building the apt source package (not a VCS
tree or similar) and see how configure is run twice. Now try again, but
touch configure before building. You shall see that configure is run
just once.

Since I do not understand the reasoning behind calling "make -s dirs" or
calling configure again from configure.mak, this bug comes without a
working patch. The only workaround I can propose is "touch configure"
before running it. Can you maybe find a better solution?

Thank you

Helmut