adapt build-checks to newer boost-libraries

[blackdoor]

Somewhere between libboost 1.35 and 1.45 some details of the packaging have changed, which causes problems with our platform checks:

• program-options, filesystem and regexp used to ship a -mt variant of the shared libraries. Guess that was deemed obsolete, who wants not to link against a threadsafe variant of the lib todays?
• moreover, boost-filesystem now also depends on boost-system. While the deb package dependencies deal with that automatically, we still need to assure that boost-system is linked for the configure check. When I encountered that problem first for Ubuntu Natty, it was even sufficient only to link against libboost_system (and include boost/filesystem.hpp)

We need to find out at which version exactly this behaviour changed, so we can build a sensible switch into the checks.

[blackdoor]

Urgency: Problem first observed when building for Ubuntu Natty, which is currently in ß stage. Yet this is a quite recent version, so maybe we can get away with just a patch in the debian package for a while, but somewhere in the next months likely people on other systems will run into the same problems

[ichthyo]

Looks like the change in the libraries happened between 1.40 and 1.42

Moreover, the actual problem with the configure check could also be caused by SCons 2.0 treating that corner case slightly different than 1.x. Actually, I'd say the behaviour of SCons 2.0 is the correct one: the configure check fails because we didn't mention the additional link dependency.

[ichthyo]

...meanwhile found out that it's sufficient to check for boost-system first, because it will then be added to the enviroment used for further checks.

Not sure about the -mt variant though. There seem to be two variants, as always. Maybe this was a problem with the ubuntu package on Natty ß-version?

Anyway, the build server is upgraded to Debian-Squeeze and we've dropped Lenny compatibility -- this Ticket could be closed, given that the next release works without adaptations on all of the supported platforms.