INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - CLOSE SEMAPHORE            
	AX = C504h
	CX:DX = semaphore handle
Return: AL = status
	    00h successful
	    FFh invalid handle
Desc:	decrement the semaphore's open count, and delete the semaphore if the
	  count reaches zero
Note:	this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
	  Alloy NTNX
SeeAlso: AX=C500h"NetWare",AX=C501h,AX=F220h/SF=04h