GN_Lab, link an alarm block into the alarm chain

RST 20H, DEFW $6C09

IN:

     BHL = pointer to alarm block (to be linked). Must have been
     previously allocated by GN_Aab.

     Fc = 0

     Fc = 1, time/date already passed
     A = error code:
          RC_BAD ($04), bad parameters

     ..BCDEHL/IXIY same
     AF....../.... different

A badly formed block is likely to crash the machine. The routine does not check the vality of the alarm block.

Related calls:

GN_Aab, allocate alarm block
GN_Alp, process an expired alarm (internal OZ usage)
GN_Fab, free alarm block
GN_Uab, unlink an alarm block from the alarm chain
OS_Alm, alarm manipulation (internal OZ usage)