Issue #10260 has been reported by Tsuyoshi Sawada.

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Bug #10260: Cannot install "thin" gem
https://bugs.ruby-lang.org/issues/10260

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: ruby 2.2.0preview1 (2014-09-17 trunk 47616) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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When I try to install "thin" gem, I get the following error:

~~~
$ sudo gem install thin
Building native extensions.  This could take a while...
ERROR:  Error installing thin:
	ERROR: Failed to build gem native extension.

    /usr/local/bin/ruby -r ./siteconf20140919-24244-x0j5an.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... yes
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... no
checking for epoll_create() in sys/epoll.h... yes
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling binder.cpp
compiling kb.cpp
compiling ssl.cpp
compiling rubymain.cpp
compiling ed.cpp
compiling cmain.cpp
compiling pipe.cpp
compiling em.cpp
em.cpp: In member function °∆void EventMachine_t::_RunEpollOnce()°«:
em.cpp:574:37: error: °∆rb_thread_select°« was not declared in this scope
   EmSelect (0, NULL, NULL, NULL, &tv);
                                     ^
em.cpp: In member function °∆int SelectData_t::_Select()°«:
em.cpp:827:67: error: °∆rb_thread_select°« was not declared in this scope
  return EmSelect (maxsocket+1, &fdreads, &fdwrites, &fderrors, &tv);
                                                                   ^
em.cpp: In member function °∆void EventMachine_t::_RunSelectOnce()°«:
em.cpp:946:40: error: °∆rb_thread_select°« was not declared in this scope
      EmSelect (0, NULL, NULL, NULL, &tv);
                                        ^
make: *** [em.o] Error 1

make failed, exit code 2

Gem files will remain installed in /usr/local/lib/ruby/gems/2.2.0/gems/eventmachine-1.0.3 for inspection.
Results logged to /usr/local/lib/ruby/gems/2.2.0/extensions/x86_64-linux/2.2.0-static/eventmachine-1.0.3/gem_make.out
~~~
I didn't have this problem with previous version of Ruby.



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