[oe] Fixing OE.dev dependency issues

[Richard Purdie]

There is a bitbake 1.8.x bug I've kind of been avoiding for a while. The
classic case is where a multithreaded bitbake tries to run a do_patch
task before do_populate_staging for quilt-native has run. This
highlights a gaping hole in our dependency information and worse still,
we have no mechanism to make bitbake aware of this dependency. There are
also more subtle bugs too.

I'm proposing we add the syntax:

do_patch[depends] = "quilt-native:populate_staging" 

to handle needs like this. Experiments on my local tree suggest we need
the following patch to generate the correct dependencies:

http://www.rpsys.net/openzaurus/temp/oe-depends-fixes.patch

but of course once we do this, bitbake 1.6 is no longer going to work
with the metadata since this change is not backwards compatible.

I'm proposing to release bitbake 1.8.2 with code to handle the above,
and epoch handling code in the very near future. We will then have to
aim to make bitbake 1.8.2 the minimum bitbake version for .dev before
the above fix can be checked in and epoch packages can be more
widely/easily used. Does anyone have any objections to a move to bitbake
1.8 in due course? What timescale would people class as acceptable?

Cheers,

Richard