thread_pthread.c: RUBY_STACK_MIN
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37402 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread_pthread.c: RUBY_STACK_MIN
fix r37079. [ruby-dev:46322] [Bug #7247]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37402 b2dd03c8-39d4-4d8f-98ff-823fe69b080e