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

1 files changed, 2 insertions, 0 deletions

diff --git a/vm_core.h b/vm_core.h
index 67c384c509..c05acb8ab7 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -123,9 +123,11 @@
 void *rb_register_sigaltstack(void);
 #  define RB_ALTSTACK_INIT(var) var = rb_register_sigaltstack()
 #  define RB_ALTSTACK_FREE(var) xfree(var)
+#  define RB_ALTSTACK(var)  var
 #else /* noop */
 #  define RB_ALTSTACK_INIT(var)
 #  define RB_ALTSTACK_FREE(var)
+#  define RB_ALTSTACK(var) (0)
 #endif
 
 /*****************/