flex 2.5.2[34] / bison 1.75b interaction

[Bruce Lilly]

FYI the following is a copy of part of a report on bison 1.75b
issues. It documents some problems with the bison/flex interface.

> Finally, there are some bad interactions between bison 1.75b
> and flex 2.5.23: bison unconditionally #defines YYLTYPE, which
> causes grief when location tracking is undesired, and flex's
> header file (generated with %option header) #defines yyout
> as a macro taking arguments, whereas bison uses yyout as a
> parameter variable name in the newfangled yysymprint function
> (please choose a different variable name). 

As far as I can tell, the same issues exist w/ flex 2.5.24.

Current workaround is:

#undef YYLTYPE
#ifndef FLEX_SCANNER
# define YY_HEADER_NO_UNDEFS
# include "mailflex.h"
# undef yyout
#endif

where mailflex.h is the flex-generated header.