thread_pthread.c: poll.h is already included

* thread_pthread.c (poll.h): already included in ruby/io.h from
  thread.c.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39965 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Makefile.sub: SIGNEDNESS_OF_TIME_T

* win32/Makefile.sub (config.h): add SIGNEDNESS_OF_TIME_T for
  TIMET_MAX and TIMET_MIN.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39966 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* time.c (num_exact): use to_r method only if to_int method is
  available.
  [ruby-core:53764] [Bug #8173] reported by Hiro Asari.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39967 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* test/-ext-/num2int/test_num2int.rb (asert_num2i_success): New
  utility method.
  (asert_num2i_error): Ditto.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39968 b2dd03c8-39d4-4d8f-98ff-823fe69b080e