Pull in pthread_stackseg_np() usage patch for OpenBSD from older

www/mozilla-firefox port.

3rdp/build/js_src_jsnativestack_cpp.patch

-$OpenBSD: patch-js_src_jsnativestack_cpp,v 1.2 2011/06/28 05:43:57 landry Exp $
-https://bugzilla.mozilla.org/show_bug.cgi?id=634609
---- js/src/jsnativestack.cpp.orig	Fri May 27 18:12:08 2011
-+++ js/src/jsnativestack.cpp	Tue May 31 22:18:21 2011
+--- js/src/jsnativestack.cpp.orig	2011-03-31 12:08:36.000000000 -0700
++++ js/src/jsnativestack.cpp	2012-10-15 13:03:20.000000000 -0700
 @@ -50,7 +50,7 @@
  #elif defined(XP_MACOSX) || defined(DARWIN) || defined(XP_UNIX)
  # include <pthread.h>
@@ -11,3 +9,42 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=634609
  #  include <pthread_np.h>
  # endif
  
+@@ -198,7 +198,9 @@
+     pthread_attr_init(&sattr);
+ #  if defined(PTHREAD_NP_H) || defined(_PTHREAD_NP_H_) || defined(NETBSD)
+     /* e.g. on FreeBSD 4.8 or newer, neundorf@kde.org */
+-    pthread_attr_get_np(thread, &sattr);
++#   if (!defined(__OpenBSD__))
++     pthread_attr_get_np(thread, &sattr);
++#   endif
+ #  else
+     /*
+      * FIXME: this function is non-portable;
+@@ -209,14 +211,24 @@
+ 
+     void *stackBase = 0;
+     size_t stackSize = 0;
+-#  ifdef DEBUG
+-    int rc = 
+-#  endif
++#  if defined(__OpenBSD__)
++	stack_t ss;
++	int rslt;
++
++	rslt = pthread_stackseg_np(pthread_self(), &ss);
++	stackBase = (void*)((size_t)ss.ss_sp - ss.ss_size);
++	stackSize = ss.ss_size;
++#  else
++#   ifdef DEBUG
++     int rc = 
++#   endif
+         pthread_attr_getstack(&sattr, &stackBase, &stackSize);
+     JS_ASSERT(!rc);
+     JS_ASSERT(stackBase);
+     pthread_attr_destroy(&sattr);
+ 
++#  endif
++
+ #  if JS_STACK_GROWTH_DIRECTION > 0
+     return stackBase;
+ #  else