%option reentrant[-bison] unrecognized?

[Aaron Stone]

Hi,

I was reading in newsgroup postings and recent flex documentataion that it now
has an option called %option reentrant and reentrant-bison to help build a
scanner that better fits with a reentrant Bison parser.

I am getting this error:

/bin/sh ./ylwrap "flex" addr-lex.l lex.yy.c addr-lex.c --  -olex.yy.c
"addr-lex.l", line 67: unrecognized %option: reentrant-bison

My flex version is 2.5.4a. Have these options not yet been released? Is there
a development CVS tree I can pull them from? Has my GNU karma run out?

Many thanks,
Aaron