Ruby

• error.c (rb_async_bug_errno): async-safe bug report function.
  In timer thread, signal handler shoul use it.
  The patch is contributed by Eric Wong normalperson@yhbt.net.
  Refs: [ruby-core:37644] and [ruby-core:37647]
• thread_pthread.c: use rb_async_bug_errno().
  And replace all fprintf() to write().
• internal.h (rb_async_bug_errno): add decl. of above func.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32274 b2dd03c8-39d4-4d8f-98ff-823fe69b080e