Since I went through the frustration of not having this work, trying to fix it, and finally fixing it, I thought I should at least share my solution/experience in case someone else needs it.
I am on Arch Linux and had recently upgraded everything (including the boost library to 1.53). I then notice we are playing on 91 still. No big deal, lets just get the source and compile it. Doesn't compile? Well, lets just apply the patch currently on the repo's pkgbuild:
(https://projects.archlinux.org/svntogit/community.git/plain/trunk/boost-1.50.patch?h=packages/spring)
Wait, it still gets stuck?:
/home/N2maniac/git/spring/spring_91.0/AI/Skirmish/E323AI/CScopedTimer.h:39:31: error: expected unqualified-id before numeric constant
boost::xtime_get(&t, boost::TIME_UTC);
^
make[2]:
* [AI/Skirmish/E323AI/CMakeFiles/E323AI.dir/CTaskHandler.cpp.o] Error 1
make[1]:
* [AI/Skirmish/E323AI/CMakeFiles/E323AI.dir/all] Error 2
make:
* [all] Error 2
Oh, turns out that file needs a similar change:
+ boost::xtime_get(&t, boost::TIME_UTC);
- boost::xtime_get(&t, boost::TIME_UTC_);
And now it gets through compilation and I can play again!