Robert Weaver's fix

  char env[MAX_PATH]; /* MAX_PATH is from windef.h */

  char *temp = getenv(variable);

  env[0] = '\0';

  if (temp != NULL)

    ExpandEnvironmentStrings(temp, env, sizeof(env));

#else

  /* no length control */

  char *env = getenv(variable);

#endif

  return env?strdup(env):NULL;

  return (env && env[0])?strdup(env):NULL;

}

char *curl_getenv(char *v)