Add thread_equal function to allow for platform defined function to

Add thread_equal function to allow for platform defined function to

2001-09-19  Sebastian Wilhelmi  <wilhelmi@ira.uka.de>

	* glib/gthread.h (GThreadFunctions): Add thread_equal function to
	allow for platform defined function to compare two threads.

	* glib/gthread.c: Use g_thread_functions_for_glib_use.thread_equal
	when non-NULL instead of ==.

	* gthread/gthread-posix.c: Add g_thread_equal_posix_impl and
	add to the function vector g_thread_functions_for_glib_use_default.

	* gthread/gthread-solaris.c, gthread/gthread-win32.c: Add NULL
	as equal function, as on those two platforms you don't need an
	equal function.