Cleanup Issue `LCM-NO-ARGUMENTS`

CLtL incorrectly states that (lcm) should return infinity, and therefore specifies that giving lcm no arguments is an error.

In point of mathematical fact, 1 is the identity for the lcm operation.

Define (lcm) to return the integer 1.

  (lcm) => 1

Currently the behavior in this case is implementation-dependent.

Doing what is mathematically right.

KCL signals an error. Lucid Lisp returns 1. Symbolics Common Lisp returns 1.

Pretty small (one-line fix).

None.

Continued embarassment for Steele.

Negligible.

Correct handling of a seldom-used boundary case.

Mild improvement.

Mentioned in Steele's December 1985 "clarifications".

Cleanup Issue LCM-NO-ARGUMENTS