char *strv_join(char **l, const char *separator) _malloc_;
-char **strv_env_merge(char **x, ...) _sentinel_;
-char **strv_env_delete(char **x, ...) _sentinel_;
+char **strv_env_merge(unsigned n_lists, ...);
+char **strv_env_delete(char **x, unsigned n_lists, ...);
+
+char **strv_env_set(char **x, const char *p);
#define STRV_FOREACH(s, l) \
for ((s) = (l); (s) && *(s); (s)++)