char **strv_env_merge(unsigned n_lists, ...);
char **strv_env_delete(char **x, unsigned n_lists, ...); /* New copy */
char **strv_env_set(char **x, const char *p); /* New copy ... */
char **strv_env_unset(char **l, const char *p); /* In place ... */
char **strv_env_merge(unsigned n_lists, ...);
char **strv_env_delete(char **x, unsigned n_lists, ...); /* New copy */
char **strv_env_set(char **x, const char *p); /* New copy ... */
char **strv_env_unset(char **l, const char *p); /* In place ... */