Using Ubuntu, when I run "bundle install" to set up my Rails environment, it throws an error during the JSON gem installation:
Installing json (1.7.3) with native extensions Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension./usr/bin/ruby1.9.1 extconf.rb /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError) from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require' from extconf.rb:1:in `<main>'Gem files will remain installed in /home/danny/.bundler/tmp/2040/gems/json-1.7.3 for inspection.Results logged to /home/danny/.bundler/tmp/2040/gems/json-1.7.3/ext/json/ext/parser/gem_make.outAn error occured while installing json (1.7.3), and Bundler cannot continue.Make sure that `gem install json -v '1.7.3'` succeeds before bundling.When I try installing only the JSON 1.7.3 gem it also gives me an error:
Building native extensions. This could take a while...ERROR: Error installing json: ERROR: Failed to build gem native extension./usr/bin/ruby1.9.1 extconf.rb/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError) from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require' from extconf.rb:1:in `<main>'Gem files will remain installed in /var/lib/gems/1.9.1/gems/json-1.7.3 for inspection.Results logged to /var/lib/gems/1.9.1/gems/json-1.7.3/ext/json/ext/parser/gem_make.outI've installed RVM and am running Ruby 1.9.3; Why can't it install the JSON gem?