I follow the instructions for icecc.bbclass in chapter 7.45 and I can not get it working.

The manual states that I on a distribution level can add the following:

    INHERIT_DISTRO += "icecc"
    ICECC_DISABLED ??= "1"

This will make sure my builders use the same sstate signatures regardless if they use icecc or not. The way I did it to test was to create my own distro layer, called mydist, that inherits from Poky.

    $ cat ../meta-mydist/conf/distro/mydist.conf

    require conf/distro/poky.conf

    DISTRO = "mydist"
    DISTRO_NAME = "MyDist"

    INHERIT_DISTRO += "icecc"
    ICECC_DISABLED ??= "1"

In my bblayers.conf I added this layer directly after the meta-yocto layer. But with this addition my build environment will not work anymore. What happens is that the variable INHERIT_DISTRO is overwritten because my layer is picked before the poky/meta/conf/distro/defaultsetup.conf. I get the same behaviour if i edit the poky.conf and not use my own distro.

    $ bitbake core-image-base -e

    ...

    #
    # $INHERIT_DISTRO [3 operations]
    #   append /work/yocto/course/meta-mydist/conf/distro/mydist.conf:6
    #     "icecc"
    #   set? /work/yocto/course/poky/meta/conf/distro/defaultsetup.conf:22
    #     "debian devshell sstate license"
    #   set /work/yocto/course/poky/meta/conf/documentation.conf:226
    #     [doc] "Lists classes that will be inherited at the distribution level. It is unlikely that you want to edit this variable."
    # computed:
    #   " icecc"
    INHERIT_DISTRO=" icecc"
    #

    ...

I would like some clarification about how to add the icecc on distro level and make it working.