If the programmer did not provide a name [_i] is used (where [i] is
   the producer's position in the right hand side).

   This syntax modification actually simplifies the code:
   - There is no more on-the-fly naming of unnamed arguments.
   - Inlining is no more restricted to semantic actions that do not use $i.

   The patch is large because:
   - This change has an impact on many modules.
   - The expected results of the bench had to be updated.

for every nonterminal symbol.

This information is displayed at log level -lg 2.
Changed the display to not include the artificial start symbols.

of flat lists.

produce the same result as the old one.

no longer used.

are checked to produce the same results.

users.

place of the old ones (removed).

[Fix], instead of the old ad hoc mechanism. Unfinished.

  for the start productions.

Removed the old [production_defs].
Renamed [production_defs2] to [rhs].

This allows defining a few small functions in it.