meta-rust-bin prepends itself to BBPATH

I noticed this while trying to mitigate #204. The current conf/layer.conf has the following line:

BBPATH =. "${LAYERDIR}:"

According to the BitBake documentation =. means to prepend a string without a space. Meaning that meta-rust-bin puts itself in front of other layers, even though the user may have ordered these layers differently.

Yocto still has no proper mechanism to patch/override .bbclass files, so we're stuck having to create a layer and put it at the top of bblayers.conf. https://yocto.yoctoproject.narkive.com/qcV9UXm4/overriding-a-class-in-custom-layer

Looking at previous issues, this seems to have been done in order to get things working for Honister: https://github.com/rust-embedded/meta-rust-bin/issues/108. https://github.com/rust-embedded/meta-rust-bin/pull/123

Would it be possible to change things back to the default BitBake has for layer.conf files?

BBPATH .= ":${LAYERDIR}"

https://docs.yoctoproject.org/5.1.2/bsp-guide/bsp.html#layer-configuration-file

Start with conf/layer.conf and inspect the BBPATH assignment discussed in the issue, then compare it with BitBake's documented layer configuration behavior. Done means the layer no longer prepends itself to BBPATH and follows the default append form; no test or additional entry point is named.