* src/vmcore/options.c (opt_verbosethreads): Added.

* src/vmcore/options.c (opt_verbosethreads): Added.
* src/vmcore/options.h (opt_verbosethreads): Likewise.

* src/vm/vm.c (XXusage): Added -verbose:threads.
(vm_create): Likewise.

* src/threads/threads-common.c (threads_create_thread): Renamed
variable thread to t.
(threads_thread_print_info): New function.
(threads_dump): Use threads_thread_print_info.

* src/threads/threads-common.h (threads_thread_print_info): Added.

* src/threads/native/threads.c (threads_init) [!NDEBUG]: Added
-verbose:threads debug-output.
(threads_startup_thread): Likewise.
(threads_attach_current_thread): Likewise.
(threads_detach_thread): Likewise.