update the Arduino demo

The generated code for tests on boolean output was wrong. Indeed, it
was generating

  if (o1 == _true) {

instead of

  if (*o1 == _true) {

nb : a warning was emited

Add code to support empty arrays (not yet working)

It was generetaing wrong code in conjunction with -ec.

In particular, it was generating n-any "and" instead of binary "and".

Also, I needed (in L2LExpandEnum) to generated a Lic.ARRAY of const
instead of a Lic.Array_const_eff so that LicDump properly generated
ec code.

which was not even compiling...

More precisely, transforms equations of the form

   y = x when Toto(c);

into

   x when Toto_c ;
   Toto_c=Toto(c);

Also, force a workflow (via a lock file named commited) that make
sure that the content of lv6version.ml is always correct xrt shat and
git commit number.