* fhandler_disk_file.cc (fhandler_disk_file::link): Revert to checking

	* fhandler_disk_file.cc (fhandler_disk_file::link): Revert to checking
	for binary in case of .exe files.
	* ntdll.h (RtlPrefixUnicodeString): Declare.
	* path.cc (path_conv::is_binary): New method.
	* path.h (path_conv::is_binary): Declare.
	* syscalls.cc (rename_append_suffix): New static helper function for
	rename.
	(rename): Rewrite.  New suffix tests.  Use native NT functions.