2011-02-10 Ivan Maidanski <ivmai@mail.ru>

2011-02-10  Ivan Maidanski  <ivmai@mail.ru>

	* os_dep.c (GC_setpagesize, GC_task_self, PROTECT, UNPROTECT):
	Reorder to remove redundant ifdef for Win32.
	* os_dep.c: Add comment to some endif.
	* os_dep.c: Include pthread.h (for Linux even if single-threaded)
	if USE_GET_STACKBASE_FOR_MAIN; also include it for Darwin.
	* os_dep.c (STACKBOTTOM): Redefine for Darwin (unless prohibited
	for some reason).
	* os_dep.c (GC_get_main_stack_base): Allow
	USE_GET_STACKBASE_FOR_MAIN for Linux even if single-threaded; add
	assertion for the returned result.
	* os_dep.c (GC_get_stack_base): Define for Darwin if
	multi-threaded.
	* os_dep.c (GC_page_was_dirty): Reformat the code.
	* os_dep.c: Reformat some comments.
	* os_dep.c (SIG_OK, CODE_OK): Add comment (for FreeBSD).
	* os_dep.c (ID_STOP, ID_RESUME): Define only if threads.
	* os_dep.c (catch_exception_raise): Remove redundant parentheses;
	refine the documentation.