Suppress bison warning in ecpg grammar.
opt_distinct_clause is only used in PLpgSQL_Expr, which ecpg
ignores, so it needs to ignore opt_distinct_clause too.
My oversight in reported by Bruce Momjian.
Discussion:
@@ -71,6 +71,7 @@ my %replace_types = (
'type_function_name' => 'ignore',
'ColLabel' => 'ignore',
'Sconst' => 'ignore',
+ 'opt_distinct_clause' => 'ignore',
'PLpgSQL_Expr' => 'ignore',
'PLAssignStmt' => 'ignore',
'plassign_target' => 'ignore',
