Re2 and lemon outdated

[madebr]

The versions of re2c and lemon in this repo are severely outdated.
I just tried to build perplex using more recent releases and did end up with a non-working perplex tokenizer.

[cshorler]

yes...

STEPcode master branch should build with the versions here. That said, to build STEPcode you shouldn't normally be rebuilding re2c, lemon or perplex output (outputs are included in the STEPcode tree)

Other STEPcode branches (develop, parser_rewrite etc) use later versions of re2c and lemon. I dropped perplex. There is an outstanding action for me to share the versions used to build those branches (where we do use some more advanced re2c features).

I'll do this.