INT 88 - APL*PLUS/PC - DETERMINE NAME STATUS
        AL = FFh
        ES:SI -> name
        CX = length of name
Return: CF set if name ill-formed or already in use
            BX = STPTR if already in symbol table
        CF clear if name is available for use
            BX = 0000h
Note:   forces the name into the workspace and makes it immune from outswapping
SeeAlso: AL=F9h,AL=FEh,INT C8"APL"