@boegel it lgtm, but I wonder where the version check comes from. I haven't seen anything in Eigen's changelog pointing to any change in cmake files or pkg-config in 3.3.4.

@damianam I don't want to make this change for old Eigen versions/easyconfigs because i) the problem hasn't popped up for older versions (I suspect because not many software packages require eigen3.pc, and ii) mainly because the change requires using CMake as a build dependency for something that is installed with dummy toolchain (since nothing is actually being compiled).
That implies that CMake itself should also be built with dummy, which leaves us at the mercy of the OS compiler for building CMake 😱

I understand........ But I would add a comment making clear where the version restriction comes from. This is an EB issue, not an eigen requirement. Normally version checks are due to changes from one version onwards, which is not the case here. Looks to me like sort of "abusing" version checks for something they are not intended for (not exactly that, but you know what I mean)

@damianam I understand the potential confusion, clarifying comment added in 175326c