* thread.cc (MTinterface::fixup_after_fork): Fix thread list after fork.

(pthread::threads): Instantiate.
(pthread::pthread): Initialize running and suspendend.
Initialize next with NULL.
Add thread to thread list if it is not the null_pthread.
(pthread::~pthread): Remove thread from thread list if it is not the null_pthread.
(pthread::postcreate): Set running flag.
(pthread::exit): Reset running flag.
(pthread::cancel): Try to cancel thread only if still running.
(pthread::_fixup_after_fork): Implement.
(pthread::detach): Check if thread is still running before detach.
* thread.h (pthread::running): New member.
(pthread::next): Ditto.
(pthread::fixup_after_fork): New static method.
(pthread::threads): New static method.
(pthread::_fixup_after_fork): New method.

winsup/cygwin/thread.h

@@ -385,11 +385,11 @@ public:
   void *(*function) (void *);
   void *arg;
   void *return_ptr;
+  bool running;
   bool suspended;
   int cancelstate, canceltype;
   HANDLE cancel_event;
   pthread_t joiner;
-  // int joinable;
 
   /* signal handling */
   struct sigaction *sigs;
@@ -442,11 +442,21 @@ public:
     return t1 == t2;
   }
 
+  /* List support calls */
+  class pthread *next;
+  static void fixup_after_fork ()
+  {
+    threads.for_each (&pthread::_fixup_after_fork);
+  }
+
 private:
+  static List<pthread> threads;
   DWORD thread_id;
   __pthread_cleanup_handler *cleanup_stack;
   pthread_mutex mutex;
 
+  void _fixup_after_fork ();
+
   void pop_all_cleanup_handlers (void);
   void precreate (pthread_attr *);
   void postcreate ();