[antlr-interest] C++ compliance of antlr generated code

[Maurizio de Pascale]

the C++ code generated by ANTLR (latest 2.7.X) uses lots of variables 
starting with '_', which is however forbidden by the standard since 
symbols starting with an underscore are reserved to the implementation.
I suggest taking care of this for the ANTLR 3 C++ target.

cheers,
Maurizio de Pascale
mdepascale at dii.unisi.it