Mysql – Installing Redmine on an NSlu2-Linux Device (QNAP)

I would like to run redmine on my NSlu2 NAS Server (QNAP) with an arm processor. I installed ipkg and so on everything runs well.

Trying to install redmine I need to install ruby-on-rails. The problem is that the my repositories install ruby version 1.9.1 which is too new for redmine and is not going to work. Does anyone know how I can downgrade ruby to 1.8.6 or 1.8.7?

Many thanks,
Ovanes

P.S.: I could probably compile the right version, but I don't like this idea. Preferred solution would be either some package I can download or the link to alternative repository.

P.P.S.: getting the pre-release Redmine version 0.9.0 started the db population script, but than it blames that I should install mysql gem. Running

gem install mysql

As well as other variation when specifying my-sql-config directory does not help I get the error:

# gem install mysql
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.

/opt/bin/ruby extconf.rb install mysql
checking for mysql_ssl_set()... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.

Provided configuration options:
--with-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/opt/bin/ruby
--with-mysql-config
--without-mysql-config
/opt/lib/ruby/1.9.1/mkmf.rb:362:in `try_do': The complier failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /opt/lib/ruby/1.9.1/mkmf.rb:415:in `try_link0'
from /opt/lib/ruby/1.9.1/mkmf.rb:419:in `try_link'
from /opt/lib/ruby/1.9.1/mkmf.rb:527:in `try_func'
from /opt/lib/ruby/1.9.1/mkmf.rb:772:in `block in have_func'
from /opt/lib/ruby/1.9.1/mkmf.rb:668:in `block in checking_for'
from /opt/lib/ruby/1.9.1/mkmf.rb:274:in `block (2 levels) in postpone'
from /opt/lib/ruby/1.9.1/mkmf.rb:248:in `open'
from /opt/lib/ruby/1.9.1/mkmf.rb:274:in `block in postpone'
from /opt/lib/ruby/1.9.1/mkmf.rb:248:in `open'
from /opt/lib/ruby/1.9.1/mkmf.rb:270:in `postpone'
from /opt/lib/ruby/1.9.1/mkmf.rb:667:in `checking_for'
from /opt/lib/ruby/1.9.1/mkmf.rb:771:in `have_func'
from extconf.rb:50:in `<main>'

Gem files will remain installed in /opt/local/lib/ruby/gems/1.9.1/gems/mysql-2.8.1 for inspection.
Results logged to /share/HDA_DATA/.qpkg/Optware/local/lib/ruby/gems/1.9.1/gems/mysql-2.8.1/ext/mysql_api/gem_make.out 

Any suggestions are highly appreciated. The suggested mkmf.log is empty. I assume that I don't have mysql source installed, but where can I get it as an Optware-Package which plays with mysql version installed.