read_environment
i = read_environment(file, &newenv);
i = read_environment(_PATH_ETC_ENVIRONMENT, env);
i = read_environment(_PATH_ETC_ENVIRONMENT, &newenv);
read_environment(const char *file, char ***env);
count = read_environment(fn, &env);
count = read_environment(fn, &env);
count = read_environment(fn, &env);