thread_pthread.c: clear altstacks in thread cache at GVL destruction
Otherwise, an altstack may live past ObjectSpace destruction and xfree-ing the altstack will segfault.
[ruby-core:85621] [Feature #14487]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64102 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread_pthread.c: clear altstacks in thread cache at GVL destruction
Otherwise, an altstack may live past ObjectSpace destruction
and xfree-ing the altstack will segfault.
[ruby-core:85621] [Feature #14487]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64102 b2dd03c8-39d4-4d8f-98ff-823fe69b080e