This function deletes a previously defined defglobal.
Syntax
(undefglobal <defglobal-name>)
If the defglobal is in use (for example if it is referred to in
a deffunction), then the deletion will fail. Otherwise, no further
uses of the deleted defglobal are permitted (unless redefined).
If the symbol * is used for <defglobal-name>, then all defglobals
will be deleted (unless there is a defglobal named *). This function
has no return value.