`.lsym SYMBOL, EXPRESSION'
==========================

   `.lsym' creates a new symbol named SYMBOL, but does not put it in
the hash table, ensuring it cannot be referenced by name during the
rest of the assembly.  This sets the attributes of the symbol to be the
same as the expression value:
     OTHER = DESCRIPTOR = 0
     TYPE = (section of EXPRESSION)
     VALUE = EXPRESSION

The new symbol is not flagged as external.