NAME
	source_file_name - return source filename of an object

SYNOPSIS
	varargs string source_file_name(mixed ob)


DESCRIPTION
	Returns the source filename of ob. The first argument is optional
	and defaults to this_object(). It may be a string or an object.
	Any ".c" at the end will be removed if config.h defines
	DEFAULT_SRC_EXTENSION.

SEE ALSO
	efun/file_name, efun/directory_name, efun/base_name
