Ruby » Ruby master

Haiku now best effort support

• configure.in: remove obsolete workarounds for Haiku.
• dln.c, file.c, io.c: remove obsolete Haiku workarounds.
• thread_pthread.c: add stack bounds detection for Haiku.
• signal.c: get stack pointer from signal context on Haiku.
  [ruby-core:67923] [Bug #10811] [Fix GH-1109]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52721 b2dd03c8-39d4-4d8f-98ff-823fe69b080e