This will generally turn off more FPU codegen, even if its using
software fallback unless the project/target/platform selects a cpu that
has FPU support. This also turns off a few blocks of test code and the
upcoming floating point printf if it's not present on the arch.
This may break projects that were compiling for say cortex-m0 but
expected FPU code to be present. If so it should be pretty easy to
override it, but not going to add that yet unless it's necessary.