自分用

common.h

#ifndef __COMMON_H__
#define __COMMON_H__

#define DEFINE_ENUM_WITH_STRINGS(name, LIST)               \
    typedef enum name                                      \
    {                                                      \
        LIST(DEFINE_ENUM_ELEMENT)                          \
    } name;                                                \
                                                           \
    static inline const char *name##_to_string(name value) \
    {                                                      \
        switch (value)                                     \
        {                                                  \
            LIST(DEFINE_ENUM_CASE)                         \
        default:                                           \
            return "UNKNOWN";                              \
        }                                                  \
    }

#define DEFINE_ENUM_ELEMENT(e) e,
#define DEFINE_ENUM_CASE(e) \
    case e:                 \
        return #e;

#endif

test.c

#include <stdio.h>
#include "common.h"

#define COLOR_ITEMS(X) \
    X(RED)             \
    X(GREEN)           \
    X(BLUE)

DEFINE_ENUM_WITH_STRINGS(Color, COLOR_ITEMS)

extern void fruits(void);

int main(void)
{
    printf("%s(%d)\n", Color_to_string(1), GREEN);
    fruits();
    return 0;
}

test2.c

#include <stdio.h>

#include "common.h"

#define FRUITS_ITEMS(X) \
    X(APPLE)            \
    X(GRAPE)            \
    X(ORANGE)

DEFINE_ENUM_WITH_STRINGS(Fruits, FRUITS_ITEMS)

void fruits(void)
{
    printf("%s(%d)\n", Fruits_to_string(2), ORANGE);
}

何かもっと良い方法があった気がするのだけど
見つけきれなかったのでとりあえずこれで

出力サンプル

tyano ~$ gcc test.c test2.c 
tyano ~$ ./a.out 
GREEN(1)
ORANGE(2)

値指定版

#include <stdio.h>

#define DEFINE_ENUM_WITH_STRINGS(Name, LIST) \
    typedef enum Name {                      \
        LIST(EXPAND_ENUM, EXPAND_ENUM_VAL)   \
    } Name;                                  \
    static const char *Name##_to_string(int v) {       \
        switch (v) {                                    \
            LIST(EXPAND_CASE, EXPAND_CASE_VAL)         \
            default: return "UNKNOWN";                 \
        }                                              \
    }

#define EXPAND_ENUM(name) name,
#define EXPAND_ENUM_VAL(name, val) name = val,

#define EXPAND_CASE(name) case name: return #name;
#define EXPAND_CASE_VAL(name, val) case name: return #name;

#define COLOR_LIST(X, X_VAL) \
    X(RED)                   \
    X(GREEN)                 \
    X(BLUE)                  \
    X_VAL(BLACK, 1000)       \
    X(WHITE)

DEFINE_ENUM_WITH_STRINGS(Color, COLOR_LIST)