I'm not quite sure why, but when installing ruby_speech on JRuby, it attempts to build the C extension rather than use the JRuby extension:
[bklang@Avondale:~/src/adhearsion] (feature/punchblock_2.0|jruby-1.7.4)
[Wed Jun 12 16:13:01]$ export JRUBY_OPTS="--1.9" # To be safe; should already be default mode
[bklang@Avondale:~/src/adhearsion] (feature/punchblock_2.0|jruby-1.7.4)
[Wed Jun 12 16:13:06]$ gem install ruby_speech
Building native extensions. This could take a while...
ERROR: Error installing ruby_speech:
ERROR: Failed to build gem native extension.
/Users/bklang/.rvm/rubies/jruby-1.7.4/bin/jruby extconf.rb
NotImplementedError: C extension support is not enabled. Pass -Xcext.enabled=true to JRuby or set JRUBY_OPTS or modify .jrubyrc to enable.
(root) at /Users/bklang/.rvm/rubies/jruby-1.7.4/lib/ruby/shared/mkmf.rb:8
require at org/jruby/RubyKernel.java:1054
(root) at /Users/bklang/.rvm/rubies/jruby-1.7.4/lib/ruby/shared/rubygems/custom_require.rb:1
(root) at extconf.rb:1
Gem files will remain installed in /Users/bklang/.rvm/gems/jruby-1.7.4/gems/ruby_speech-2.1.2 for inspection.
Results logged to /Users/bklang/.rvm/gems/jruby-1.7.4/gems/ruby_speech-2.1.2/ext/ruby_speech/gem_make.out
[Last command returned error 1]
[bklang@Avondale:~/src/adhearsion] (feature/punchblock_2.0|jruby-1.7.4)
[Wed Jun 12 16:13:19]$
I'm not quite sure why, but when installing ruby_speech on JRuby, it attempts to build the C extension rather than use the JRuby extension: