sql_yacc.yy:

  Make "FRAC_SECOND"/"SQL_TSI_FRAC_SECOND" non-reserved words,
  must like "SECOND"/"SQL_TSI_SECOND", "MINUTE"/"SQL_TSI_MINUTE",
  etc.
  Will wait for okay to push. (It doesn't break any tests.)

sql/sql_yacc.yy

@@ -6795,6 +6795,7 @@ keyword:
 	| FIRST_SYM		{}
 	| FIXED_SYM		{}
 	| FLUSH_SYM		{}
+	| FRAC_SECOND_SYM	{}
 	| GEOMETRY_SYM		{}
 	| GEOMETRYCOLLECTION	{}
 	| GET_FORMAT		{}