Bison 3.5.91 now defaults parse.error to "simple"

parse.y

@@ -1014,6 +1014,7 @@ static int looking_at_eol_p(struct parser_params *p);
 
 %expect 0
 %define api.pure
+%define parse.error verbose
 %lex-param {struct parser_params *p}
 %parse-param {struct parser_params *p}
 %initial-action

tool/pure_parser.rb

@@ -18,3 +18,4 @@ BEGIN {
   ARGV.push(file)
 }
 $_.sub!(/^%define\s+api\.pure/, '%pure-parser')
+$_.sub!(/^%define\s+.*/, '')