Add overlay_list script.

Add overlay_list script.

This script generates the list of overlays, including variant
overlays, for a particular board/variant combination.  It will
be called from setup_board.

[robotboy, 2010-08-02 21:01:03]

I'm pulling out the overlay list generation code from setup_board because it's
become large enough to be confusing.  This change does reorder the inclusion of
some overlays to put the public variant overlays before the private overlays.  I
don't think this will cause any problems.  I'll be testing this when I make the
change to setup_board.

[Antoine Labour, 2010-08-02 21:53:33]

http://codereview.chromium.org/3080019/diff/1/2
File overlay_list (right):

http://codereview.chromium.org/3080019/diff/1/2#newcode17
overlay_list:17: "The name of the board to set up."
4 spaces for line continuations. Though in general, I'd avoid them if they're
not necessary.

http://codereview.chromium.org/3080019/diff/1/2#newcode52
overlay_list:52: warn "No board overlay found. [${PRIMARY_BOARD_OVERLAY}]"
warn goes to stdout. I think it may be dangerous/hard to debug to emit this
message as is if this script is expected to be back-quoted. Redirect to stderr ?

http://codereview.chromium.org/3080019/diff/1/2#newcode79
overlay_list:79: -name "overlay-${FLAGS_board}-*" | sort -r)
As discussed, I don't think we use that globbing feature any more. just make it
look for -private

[robotboy, 2010-08-02 23:50:52]

Comments addressed, PTAL.

http://codereview.chromium.org/3080019/diff/1/2
File overlay_list (right):

http://codereview.chromium.org/3080019/diff/1/2#newcode17
overlay_list:17: "The name of the board to set up."
Cut and paste from setup_board, fixed.

http://codereview.chromium.org/3080019/diff/1/2#newcode52
overlay_list:52: warn "No board overlay found. [${PRIMARY_BOARD_OVERLAY}]"
Since this check is also done in setup_board I'm removing the warn case and
negating the conditional.

http://codereview.chromium.org/3080019/diff/1/2#newcode79
overlay_list:79: -name "overlay-${FLAGS_board}-*" | sort -r)
Done

[Antoine Labour, 2010-08-02 23:58:37]

LGTM