instrument: fetch flags from the file itself.
instrument: fetch flags from the file itself.

	* build-aux/instrument (shellwords.pl): Require and use it instead of
	dumb splitting on spaces.
	(getargs): Use @flags instead of repeating it value.
	(instrument_prefix): Use the global variables.
	Handle $libtool here to avoid uselessly complex commands when
	there is no instrumentation.
	Also resolve the mode_auto here.
	(file_flags): New.
	(instrument): Use it.

aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport