Here’s a minimal example of what I’m trying to do:

enum color { RED, GREEN, BLUE };
typedef enum legacy_color enum color;

int
main(void)
{
    return 0;
}

Compilation fails with

test.c:13:27: error: two or more data types in declaration specifiers
   13 | typedef enum legacy_color enum color;
      |                           ^~~~
test.c:13:32: warning: empty declaration with storage class specifier does not redeclare tag
   13 | typedef enum legacy_color enum color;
      |                                ^~~~~

Motivation: I need to rename an enum to align with current naming conventions in my project. The old name needs to remain as an alias, which will be declared in a compatibility header file. Referring back to my example, enum color { RED, GREEN, BLUE } will be in the main header file, and typedef enum legacy_color enum color would go in the backward-compatibility header file.

The only other approach I’ve been able to come up with is #define legacy_color color, but that’s overly broad and would match outside the enum type context.