[oe] Standalone gcc library builds

[Richard Purdie]

On Mon, 2010-03-29 at 10:42 -0700, Khem Raj wrote:
> I have had gcc build all runtimes libraries separately. I think we should
> device gcc build and we can disable building certain directories via
> --disable-<dir>. We dont have to stash libgcc. Its not a big library and
> its probably better to rebuild it along with rest of runtime libraries IMO
> and probably we should have packages for each language runtime so people
> who dont need C++ or Java or fortran dont have to build those. The same
> should be tunable in gcc builds too.

I talked with Khem on irc but just for the record here, I've done some
testing with gcc 4.3.3 in Poky and have pushed my results to:

http://git.pokylinux.org/cgit.cgi/poky/log/?h=master-gcc-runtime-testing

This adds a gcc-runtime recipe which builds libgcc, libssp and libstdc++
as test cases. It will be possible to build other runtime libs
conditionally on whether they're enabled like libfortran easily enough.

We have to add in an extra dependency layer to the compiler bootstrap
but that isn't an issue.

The bit that is ugly is the stashing of headers in staging by gcc-cross.
The issue is we want to build the target libs in our normal "target"
context so cross.bbclass is not used by gcc-runtime. This means
HOST==TARGET and hence building gcc itself fails.

Discussion on how best to do this welcome :)

Cheers,

Richard