[yocto] specify compiler version in recipe

[Trevor Woerner]

Hello,

It looks like I already know the answer to this one... ;-)

I'm guessing it isn't possible to specify the compiler version in a
recipe? That's probably way too late in the parse stage?

There are some vendor Linux kernels for some BSPs that are old enough to
pre-date the:

    fatal error: linux/compiler-gcc5.h: No such file or directory

issue. Which means we have to rely on users reading the README and
updating their conf/local.conf files to include

    GCCVERSION = "4.9%"

Unfortunately that process is error-prone. It would be great to have
that occur automatically. In other words: if you want to use the
community/default/upstream kernel then use the latest compiler (but you
won't have accelerated graphics). If you want accelerated graphics then
you have to PREFER an older kernel *and* specify which version of gcc to
use in your conf/local.conf.

Can anyone think of a clever trick for this one?

Are BSP maintainers patching their old kernels to support post-gcc-5.0
versions?

Best regards,
    Trevor