* cygthread.cc (cygthread::stub): Revert previous change and again subsume

cygthread::stub2.  Just return from function now since ExitThread is guaranteed
by automatic _threadinfo wrapper.  Define as per ThreadProc convention.
(cygthread::stub2): Remove.
(cygthread::simplestub): Perform similar operations to cygthread::stub.
(cygthread::simplestub2): Remove.
* cygthread.h (cygthread::stub): Declare as per ThreadProc convention.
(cygthread::stub2): Remove declaration.
(cygthread::simplestub): Declare as per ThreadProc convention.
(cygthread::simplestub2): Remove declaration.
* cygtls.h (_threadinfo::call): Define first argument as per ThreadProc
convention.
(_threadinfo::call2): Ditto.
(_tlsbase): Define as char * pointer.
(_tlstop): New definition.
(_main_tls): Define here.
* dcrt0.cc (alloc_stack): Revert previous change which called init_thread since
information would be overwritten by fork later anyway.
(dll_crt0_1): Use _tlsbase and _tlstop for setting stack bottom, top.
* exceptions.cc: Move _main_tls declaration to cygtls.h.
(_threadinfo::call): Define first argument as per ThreadProc convention.
(_threadinfo::call2): Call ExitThread with thread function return value.
(_threadinfo::init_thread): Don't initialize cygtls to zero if input arg is
NULL.
* fork.cc (fork_child): Reset _main_tls here.  Reinitialize parts of _my_tls
after copying data from parent.
* init.cc (threadfunc_fe): New function.  Front-end for all threads created in
cygwin processes.
(munge_threadfunc): New function.
(dll_entry): Call munge_threadfunc to force the call of a thread wrapper.
* thread.cc (pthread::thread_init_wrapper): Perform similar operations to
cygthread::stub.
(pthread::thread_init_wrapper2): Remove.
* thread.h (pthread::thread_init_wrapper): Declare as per ThreadProc
convention.
(pthread::thread_init_wrapper2): Remove declaration.
* window.cc (Winmain): Just return from function now since ExitThread is
guaranteed by automatic _threadinfo wrapper.

winsup/cygwin/fork.cc

@@ -262,8 +262,8 @@ fork_child (HANDLE& hParent, dll *&first_dll, bool& load_dlls)
      Exit with a status code of 0. */
   if (fork_info->stacksize)
     {
-      ((DWORD *)fork_info->stackbottom)[-17] = (DWORD)do_exit;
-      ((DWORD *)fork_info->stackbottom)[-15] = (DWORD)0;
+      _main_tls = &_my_tls;
+      _my_tls.init_thread (NULL);
     }
 
   set_file_api_mode (current_codepage);