Is it allowed for srand(0) to have the same effect as srand(1)?

Is it allowed for srand(0) to have the same effect as srand(1)?

C11, 7.22.2.2 The srand function (empahasis added):

The srand function uses the argument as a seed for a new sequence of pseudo-random numbers to be returned by subsequent calls to rand.

However, in glibc srand(0) has the same effect as srand(1):

  /* We must make sure the seed is not 0.  Take arbitrarily 1 in this case.  */
  if (seed == 0)
    seed = 1;

Hence, the same sequence of pseudo-random numbers is returned by subsequent calls to rand, which is confusing.

Extra: We see that in MSVC srand(0) does not have the same effect as srand(1).