INT 16 U - PCIBM PC Tools v8+ VSAFE - SET HOTKEY DISABLE FLAG
AX = FA05h
DX = 5945h
BL = new value of hotkey disable flag (nonzero to disable hotkey)
Return: CF clear
DI = 4559h
Note: this function is a NOP under VWATCH, merely returning CF clear/DI=4559h
SeeAlso: AX=FA00h,AX=FA04h