handle changes in bison 3.x * acinclude.m4 (OCTAVE_PROG_BISON): Also check for the proper way to declare api.prefix. * build-aux/common.mk (BISON_API_PREFIX_DECL_STYLE): New variable. * lex.ll: Conditionally define YYSTYPE. * oct-parse.in.yy (%API_PREFIX_DECL%): Allow for differences in the way api.prefix is specified in different versions of bison. * libinterp/parse-tree/module.mk (parse-tree/oct-parse.yy): Also substitute %API_PREFIX_DECL% in lex.ll.

Copyright notices are intentionally omitted from the files in the
examples directory.  We don't want copyright notices cluttering the
manual.