I've been playing around with Sup (I'll come to that in another post soon, fingers crossed), but couldn't get the xapian-full gem to install on Linux as it bombed out as follows:
gem install xapian-full
Building native extensions.  This could take a while...
...
checking whether the C compiler works... no
configure: error: in `/home/me/.rvm/gems/ruby-1.9.2-p290/gems/xapian-full-1.2.3/xapian-core-1.2.3':
configure: error: C compiler cannot create executables
See `config.log' for more details.
rake aborted!


Tasks: TOP => default
(See full trace by running task with --trace)


Gem files will remain installed in /home/me/.rvm/gems/ruby-1.9.2-p290/gems/xapian-full-1.2.3 for inspection.
Results logged to /home/me/.rvm/gems/ruby-1.9.2-p290/gems/xapian-full-1.2.3/./gem_make.out
And checking config.log I got:
configure:3866: checking whether the C compiler works
configure:3888: gcc   -R/home/me/.rvm/gems/ruby-1.9.2-p290/gems/xapian-full-1.2.3/lib conftest.c  >&5
gcc: error: unrecognized option '-R'
configure:3892: $? = 1
configure:3930: result: no
I found this post on archlinux (which almost exactly explains what to do, I just didn't quite get it at the time) and this github issue but it took me awhile to figure out how to apply the patch. It's always easy when you know how...
gem fetch xapian-full
gem unpack xapian-full-1.2.3.gem
cd xapian-full-1.2.3
curl -O https://github.com/rlane/xapian-full/pull/4.patch
patch < 4.patch
gem build xapian-full.gemspec
gem install ./xapian-full-1.2.3.gem
cd ..
rm -rf xapian-full-1.2.3
rm xapian-full-1.2.3.gem
I thought after unpacking I'd just be able to run rake and install the gem that way, but if you can I can't figure out how. So repacking it (build) it is - at least that doesn't take long.
Have to say, Ruby on Linux has been a lot fiddlier than I thought. On my ancient OSX 10.5 PPC no problems at all installing xapian and sup. Colour me suprised.