* src/symtab.c (symbol_check_alias_consistency): Also check

* src/symtab.c (symbol_check_alias_consistency): Also check
type names, destructors, and printers.
Reported by Alexandre Duret-Lutz.
Recode the handling of associativity and precedence in terms
of symbol_precedence_set.
Accept no redeclaration at all, not even equal to the previous
value.
(redeclaration): New.
Use it to factor redeclaration complaints.
(symbol_make_alias): Don't set the type of the alias, let
symbol_check_alias_consistency do it as for other features.
* src/symtab.h (symbol): Add new member prec_location, and
type_location.
* src/symtab.c (symbol_precedence_set, symbol_type_set): Set them.
* tests/input.at (Incompatible Aliases): New.