Rails kann einige Gems nicht installieren

[w1cked]

Hab leider mit einigen Ruby on Rails Gems Probleme beim installieren. Bis jetzt sind das Thin und Sqlite3. Im Falle von Sqlite3 hab ich folgende fehlermeldung:

DiskStation> gem install sqlite3
Building native extensions. This could take a while...
ERROR: Error installing sqlite3:
ERROR: Failed to build gem native extension.

/opt/bin/ruby extconf.rb
checking for sqlite3.h... *** 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-sqlite3-dir
--without-sqlite3-dir
--with-sqlite3-include
--without-sqlite3-include=${sqlite3-dir}/include
--with-sqlite3-lib
--without-sqlite3-lib=${sqlite3-dir}/lib
--enable-local
--disable-local
/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:431:in `try_cpp'
from /opt/lib/ruby/1.9.1/mkmf.rb:828:in `block in find_header'
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:827:in `find_header'
from extconf.rb:34:in `<main>'


Gem files will remain installed in /opt/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.6 for inspection.
Results logged to /opt/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.6/ext/sqlite3/gem_make.out

Ich finde leider nicht raus was ihm da fehlt. Das mkmf.log ist leer.
Hat jemand schon Erfahrung damit und kann mir vielleicht weiter helfen?