2010-07-28 Ivan Maidanski <ivmai@mail.ru> (mostly really Noah Lavine)

2010-07-28  Ivan Maidanski <ivmai@mail.ru> (mostly really Noah Lavine)

	* configure.ac (NO_EXECUTE_PERMISSION): Add comment.
	* doc/README.macros (NO_EXECUTE_PERMISSION): Update the
	documentation.
	* include/gc.h (GC_set_pages_executable, GC_get_pages_executable):
	New API function declaration.
	* include/gc.h (GC_ignore_warn_proc): Reformat the comment.
	* os_dep.c (OPT_PROT_EXEC): Remove (superseded by
	pages_executable).
	* os_dep.c (pages_executable): New static variable.
	* os_dep.c (IGNORE_PAGES_EXECUTABLE): New macro (used by
	GC_get_pages_executable only).
	* os_dep.c (GC_unix_mmap_get_mem, GC_remap, PROTECT, UNPROTECT):
	Replace OPT_PROT_EXEC with pages_executable.
	* os_dep.c (GC_unix_mmap_get_mem, GC_remap, GC_win32_get_mem,
	GC_wince_get_mem, UNPROTECT): Undefine IGNORE_PAGES_EXECUTABLE.
	* os_dep.c (GC_win32_get_mem, GC_wince_get_mem, GC_remap, PROTECT,
	UNPROTECT): Use PAGE_EXECUTE_... only if pages_executable is on.
	* os_dep.c (GC_set_pages_executable, GC_get_pages_executable): New
	API function definition.