* module/language/c99/compiler.mes (struct-field): Add struct tag to
struct/union types.
(field-type, field-size, field-offset, field-field, ast-type->type):
Ascertain struct tag with type.
* (expr->accu*): Do not add struct tag.
* scaffold/tests/75-struct-union.c: Test it.
* scaffold/tests/71-struct-array.c: Update.
* module/language/c99/compiler.mes (field:name): New function.
(decl->info): Use it.
(struct-field): Support anonymous union.
(field:size): Update.
(field-field): Update.
(field-offset): Update.