fcm make: build: making compiler errors more visible

[matthewrmshin]

Now that the build system continues as much as possible, the error message from a compiler failure can be buried in the middle of the log. This can make it harder for users on quick development cycle.

We should investigate ways to see if it is possible to get error messages printed at the bottom of the log instead.

(Ideally, we should have a mode to stop building more targets as soon as the 1st error occurs, but that will require a bit more redesigning of the system, e.g. moving from a state dump system into a relational database system.)