error: result of comparison against a string literal is unspecified (use an explicit string comparison function instead) [-Werror,-Wstring-compare]
    if (user->profile_pic[0] != "\0") {
int print_user(const User *user) {
    if (!user) {
        // if the user is NULL
        return -1;
    }

    if (user->profile_pic[0] != "\0") {
        // if user has profile picture, print picture
    }

    printf("Name: %s\n", user->name);
    printf("------------------------------------------");
    printf("Friends:\n");
    int i = 0;
    while (i < MAX_FRIENDS && user->friends[i]) {
        printf("%s\n", user->friends[i]->name);
        i++;
    }
    printf("------------------------------------------");
    printf("Posts:\n");
    
    Post *head = user->first_post;

    while (head->next != NULL) {
        printf("From: %s\n", user->first_post->author);
        printf("Date: %s\n\n", ctime(user->first_post->date));
        printf("%s\n\n", user->first_post->contents);
        printf("===\n");
    }
    printf("------------------------------------------");
    return 0;
}