The values of `yytext` and `yyleng` might not be properly defined when
the error function is called (in particular if the lexer reached EOF).
While this might just cause non-printable characters in the output, it
could actually lead to a crash depending on where `yytext` points.
Closesstrongswan/strongswan#346.
There is a conflict between Flex's bison-bridge and Bison's api.prefix
options. Apparently, the former was added without consulting the Bison
devs and requires YYSTYPE, which is not added to the header anymore by
the latter. Instead, we just provide the proper definition of yyflex()
manually (as recommended by the Bison docs), so the option is not
required anymore.
The parser simply returns key/value pairs of all sections, it already
resolves also= and allows overriding options in all included sections
(not only %default), options set in included section can also be cleared
again (key=).
It provides other improvements too, like quoted strings (with escape
sequences), unlimited includes and better whitespace/comment handling.
Tobias Brunner