Better Pedometer - HELP NEEDED!

I have played around for a few hours this evening. I didn't have any success compiling Gordon's test arness, even though the instructions were straight forward. Is there anything obvious to you?

$ make
gcc -std=c99 main.c -o main
In file included from main.c:55:
../Espruino/libs/misc/stepcount.c:19:10:­ fatal error: jsutils.h: No such file or directory
   19 | [#include](https://forum.espruino.com/se­arch/?q=%23include) "jsutils.h"
      |          ^~~~~~~~~~~
compilation terminated.
make: *** [Makefile:2: all] Error 1