31:  "too many links",
	32:  "broken pipe",
	33:  "numerical argument out of domain",
	34:  "numerical result out of range",
	35:  "resource deadlock avoided",
	36:  "file name too long",
	37:  "no locks available",
	38:  "function not implemented",
	39:  "directory not empty",
	40:  "too many levels of symbolic links",
	42:  "no message of desired type",
	43:  "identifier removed",

	case align%2 == 0:
		return 2
	}
	return 1
}

// mergePoint finds a block among a's blocks which dominates b and is itself
// dominated by all of a's blocks. Returns nil if it can't find one.
// Might return nil even if one does exist.
func mergePoint(b *Block, a ...*Value) *Block {
	// Walk backward from b looking for one of the a's blocks.

	// Max distance
	d := 100

	for d > 0 {
		for _, x := range a {

	71: "too many levels of remote in path",
	72: "RPC struct is bad",
	73: "RPC version wrong",
	74: "RPC prog. not avail",
	75: "program version wrong",
	76: "bad procedure for program",
	77: "no locks available",
	78: "function not implemented",
	79: "inappropriate file type or format",
	80: "authentication error",
	81: "need authenticator",
	82: "identifier removed",
	83: "no message of desired type",

	71: "too many levels of remote in path",
	72: "RPC struct is bad",
	73: "RPC version wrong",
	74: "RPC prog. not avail",
	75: "program version wrong",
	76: "bad procedure for program",
	77: "no locks available",
	78: "function not implemented",
	79: "inappropriate file type or format",
	80: "authentication error",
	81: "need authenticator",
	82: "identifier removed",
	83: "no message of desired type",

	71: "too many levels of remote in path",
	72: "RPC struct is bad",
	73: "RPC version wrong",
	74: "RPC prog. not avail",
	75: "program version wrong",
	76: "bad procedure for program",
	77: "no locks available",
	78: "function not implemented",
	79: "inappropriate file type or format",
	80: "authentication error",
	81: "need authenticator",
	82: "identifier removed",
	83: "no message of desired type",

	71: "too many levels of remote in path",
	72: "RPC struct is bad",
	73: "RPC version wrong",
	74: "RPC program not available",
	75: "program version wrong",
	76: "bad procedure for program",
	77: "no locks available",
	78: "function not implemented",
	79: "inappropriate file type or format",
	80: "authentication error",
	81: "need authenticator",
	82: "IPsec processing failure",
	83: "attribute not found",

	71: "too many levels of remote in path",
	72: "RPC struct is bad",
	73: "RPC version wrong",
	74: "RPC prog. not avail",
	75: "program version wrong",
	76: "bad procedure for program",
	77: "no locks available",
	78: "function not implemented",
	79: "inappropriate file type or format",
	80: "authentication error",
	81: "need authenticator",
	82: "identifier removed",
	83: "no message of desired type",

	{45, "EDEADLK", "deadlock condition if locked"},
	{46, "ENOTREADY", "device not ready"},
	{47, "EWRPROTECT", "write-protected media"},
	{48, "EFORMAT", "unformatted or incompatible media"},
	{49, "ENOLCK", "no locks available"},
	{50, "ENOCONNECT", "cannot Establish Connection"},
	{52, "ESTALE", "missing file or filesystem"},
	{53, "EDIST", "requests blocked by Administrator"},
	{55, "EINPROGRESS", "operation now in progress"},

	31:  "too many links",
	32:  "broken pipe",
	33:  "numerical argument out of domain",
	34:  "numerical result out of range",
	35:  "resource deadlock avoided",
	36:  "file name too long",
	37:  "no locks available",
	38:  "function not implemented",
	39:  "directory not empty",
	40:  "too many levels of symbolic links",
	42:  "no message of desired type",
	43:  "identifier removed",

	71: "too many levels of remote in path",
	72: "RPC struct is bad",
	73: "RPC version wrong",
	74: "RPC prog. not avail",
	75: "program version wrong",
	76: "bad procedure for program",
	77: "no locks available",
	78: "function not implemented",
	79: "inappropriate file type or format",
	80: "authentication error",
	81: "need authenticator",
	82: "IPsec processing failure",
	83: "attribute not found",