[oe] [RFC][PATCH] meta-toolchain: make SDK relocatable by using $SDK_PATH var in env setup script

[Richard Purdie]

On Thu, 2010-02-04 at 14:07 -0500, Denys Dmytriyenko wrote:
> On Thu, Feb 04, 2010 at 01:42:50PM -0500, Chris Conroy wrote:
> > On Thu, 2010-02-04 at 12:22 -0500, Denys Dmytriyenko wrote:
> > > First of all, they are the same. Check conf/bitbake.conf:
> > > 
> > > SDKPATH = "${SDK_PATH}"
> > > 
> > > Second, ask RP why he introduced SDKPATH, when we had SDK_PATH for years (my 
> > > guess - that's what is used in Poky, so makes porting changes easier):
> > Fair enough, but saying 'ask RP' doesn't justify away the fact that
> > having these two variables is confusing. If they really are the same,
> > then one should be removed. If one shouldn't be removed, then there is
> > some difference that should probably be documented. It's just a matter
> > of consistency/readability.
> 
> All I was trying to say is that, while it's a valid question, it is out of 
> scope of this patch. I don't want to mix 2 things in one patch (if we decide 
> to remove one of SDKPATH/SDK_PATH). And it would still be good to hear RP's 
> rationale.

As best I remember, historically, there was SDK_PREFIX. When we created
the SDK_ variables, this conflicted with things like TARGET_PREFIX,
HOST_PREFIX and BUILD_PREFIX so it had to be renamed. OE went with
SDK_PATH, Poky went with SDKPATH. When I merged a load of toolchain
stuff between the two, I think I realised halfway through a merge there
was a problem and inserted that variable to make sure everything worked.
I'm sure I intended to clean it up at some point but never got around to
it.

In summary, one needs to go. 

I have a preference for not having an underscore in the name as SDKPATH
does something different to the other SDK_*, TARGET_*, HOST_* and
BUILD_* variables and does not have a counterpart.

Cheers,

Richard