title: Eventmachine issue when installing (when installing Middleman)
body: <p>It's not a duplicated of <a href="https://stackoverflow.com/questions/17361958/eventmachine-gem-install-fail">Eventmachine gem install fail</a>, that's for Windows, and I'm running on OSX 10.9.5 and ruby ruby 2.2.0p0 </p>
  
  <p>I'm struggling to get Eventmachine installed, after I installed Middleman. Any advice on how to proceed?
  I already tried sudo gem install eventmachine -v '1.0.3' and gem install eventmachine -v 1.0.4 but no luck.</p>
  
  <pre><code>  Building native extensions.  This could take a while...
    ERROR:  Error installing eventmachine:
      ERROR: Failed to build gem native extension.
  
        /Users/malditojavi/.rvm/rubies/ruby-2.2.0/bin/ruby -r ./siteconf20150115-4062-w3t883.rb extconf.rb
    checking for rb_trap_immediate in ruby.h,rubysig.h... no
    checking for rb_thread_blocking_region()... no
    checking for inotify_init() in sys/inotify.h... no
    checking for __NR_inotify_init in sys/syscall.h... no
    checking for writev() in sys/uio.h... yes
    checking for rb_wait_for_single_fd()... yes
    checking for rb_enable_interrupt()... no
    checking for rb_time_new()... yes
    checking for sys/event.h... yes
    checking for sys/queue.h... yes
    creating Makefile
  
    make "DESTDIR=" clean
  
    make "DESTDIR="
    compiling binder.cpp
    compiling cmain.cpp
    compiling ed.cpp
    compiling em.cpp
    em.cpp:827:9: error: use of undeclared identifier 'rb_thread_select'; did you mean 'rb_thread_fd_select'?
            return EmSelect (maxsocket+1, &amp;fdreads, &amp;fdwrites, &amp;fderrors, &amp;tv);
                   ^~~~~~~~
                   rb_thread_fd_select
    ./em.h:25:20: note: expanded from macro 'EmSelect'
      #define EmSelect rb_thread_select
                       ^
    /Users/malditojavi/.rvm/rubies/ruby-2.2.0/include/ruby-2.2.0/ruby/intern.h:454:5: note: 'rb_thread_fd_select' declared here
    int rb_thread_fd_select(int, rb_fdset_t *, rb_fdset_t *, rb_fdset_t *, struct timeval *);
        ^
    em.cpp:827:32: error: cannot initialize a parameter of type 'rb_fdset_t *' with an rvalue of type 'fd_set *'
            return EmSelect (maxsocket+1, &amp;fdreads, &amp;fdwrites, &amp;fderrors, &amp;tv);
                                          ^~~~~~~~
    /Users/malditojavi/.rvm/rubies/ruby-2.2.0/include/ruby-2.2.0/ruby/intern.h:454:42: note: passing argument to parameter here
    int rb_thread_fd_select(int, rb_fdset_t *, rb_fdset_t *, rb_fdset_t *, struct timeval *);
                                             ^
    em.cpp:946:6: error: use of undeclared identifier 'rb_thread_select'; did you mean 'rb_thread_fd_select'?
                                            EmSelect (0, NULL, NULL, NULL, &amp;tv);
                                            ^~~~~~~~
                                            rb_thread_fd_select
    ./em.h:25:20: note: expanded from macro 'EmSelect'
      #define EmSelect rb_thread_select
                       ^
    /Users/malditojavi/.rvm/rubies/ruby-2.2.0/include/ruby-2.2.0/ruby/intern.h:454:5: note: 'rb_thread_fd_select' declared here
    int rb_thread_fd_select(int, rb_fdset_t *, rb_fdset_t *, rb_fdset_t *, struct timeval *);
        ^
    3 errors generated.
    make: *** [em.o] Error 1
  
    make failed, exit code 2
  
    Gem files will remain installed in /Users/malditojavi/.rvm/rubies/ruby-2.2.0/lib/ruby/gems/2.2.0/gems/eventmachine-1.0.3 for inspection.
    Results logged to /Users/malditojavi/.rvm/rubies/ruby-2.2.0/lib/ruby/gems/2.2.0/extensions/x86_64-darwin-13/2.2.0/eventmachine-1.0.3/gem_make.out
  </code></pre>