NAME
    FreeSignal -- free a signal bit

SYNOPSIS
    FreeSignal(signalNum)
               D0

    void FreeSignal(BYTE);

FUNCTION
    This function frees a previously allocated signal bit for reuse.
    This call must be performed while running in the same task in which
    the signal was allocated.

WARNING
    Signals may not be allocated or freed from exception handling code.

NOTE
    Starting with V37, an attempt to free signal -1 is harmless.

INPUTS
    signalNum - the signal number to free {0..31}.