Alternative to -DCPU_TPS

At the moment the clock speed of the CPU is hard-coded in the form of a compile-time constant in examples/Makefile.am and src/Makefile.am.

We should find a better way of doing this. Plus, we should make sure the same value is set in both Makefiles (if there is no better alternative), which is not the case in the current master (!).

Is there a way to recover that information at configure time ? Or at the start of the runtime ?

In the worst case we could run a small piece of code with sleep(1) and count the ticks. This could be executed at configure time to construct the constant. However, modern CPUs speed-up when only one core is used, which would completely bias the measurement.