total := serverPools.TotalAvailable()
	if total == 0 {
		return -1
	}
	// choose when we reach this many
	choose := rand.Uint64() % total
	atTotal := uint64(0)
	for _, pool := range serverPools {
		atTotal += pool.Available
		if atTotal > choose && pool.Available > 0 {
			return pool.Index
		}
	}
	// Should not happen, but print values just in case.

      environ_cp['TF_NEED_CLANG'] = str(choose_compiler(environ_cp))
      if environ_cp.get('TF_NEED_CLANG') == '1':
        clang_compiler_path = set_clang_compiler_path(environ_cp)
        clang_version = retrieve_clang_version(clang_compiler_path)
        disable_clang_offsetof_extension(clang_version)
    if is_windows():
      environ_cp['TF_NEED_CLANG'] = str(choose_compiler_Win(environ_cp))

   * cartesian set is constructed, the input sets are merely copied. Only as the resulting set is
   * iterated are the individual lists created, and these are not retained after iteration.
   *
   * @param sets the sets to choose elements from, in the order that the elements chosen from those
   *     sets should appear in the resulting lists
   * @param <B> any common base class shared by all axes (often just {@link Object})

   * returned to the caller, although this is neither guaranteed to occur nor required to be
   * consistent. For example, this method <i>might</i> choose to pass through recognized
   * implementations of {@code PeekingIterator} when the behavior of the implementation is known to
   * meet the contract guaranteed by this method.
   *

	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
)

// Random number state.
// We generate random temporary file names so that there's a good
// chance the file doesn't exist yet.
var (
	randN  uint32
	randmu sync.Mutex
)

// Temp files created in default Tmp dir
var globalTestTmpDir = os.TempDir()