[OE-core] [pull-oe-uboot 1/2] u-boot: remove UBOOT_MACHINE and COMPATIBLE_MACHINES

[Phil Blundell]

On Thu, 2011-05-26 at 15:37 +0100, Richard Purdie wrote:
> u-boot in OE-Core would need something like COMPATIBLE_MACHINE = ""
> which makes this harder.

Yes, true.  I don't think that's a major problem, though, you just need
a regex that won't match anything.  Something like:

COMPATIBLE_MACHINE = "(?!^)"

would probably do what you want, though it does have the admitted
downside of looking rather like line noise.  

If this is going to be a common problem then it might be worth hacking
base.bbclass about a bit to provide a more convenient way to do it.  The
UBOOT_MACHINE thing is fine as a solution for u-boot since that variable
needs to exist anyway, but I wouldn't have been keen on introducing it
just to control the recipe acceptability.

> Its usually seem to work out easier to just do:
> 
> COMPATIBLE_MACHINE_mymachine = "mymachine"
> 
> which avoids several potential issues.

Yeah, that would work fine too: you could even save a bit of typing by
just using "" as the rvalue since an empty C_M will (somewhat
counterintuitively) permit everything.  I got the impression from
Darren's original phraseology of "resorting to machine-specific
overrides" that he didn't like it much, though.

p.