pbulk and distbb depends on DEPENDS and BUILD_DEPENDS.
For what it's worth, pbulk relies only on _ALL_DEPENDS
Ok. I was wrong about pbulk but distbb uses BUILD_DEPENDS and DEPENDS.
Let's try once again. TOOL_DEPENDS you implemented is absolutely necessary for cross-compilation and I'm fine with it. But it adds nothing for native builds. As a result, you break backward compatibility for no reason.