INT 21 - DOS 2+ - "RMDIR" - REMOVE SUBDIRECTORY
	AH = 3Ah
	DS:DX -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. pathname of directory to be removed
Return: CF clear if successful
	    AX destroyed
	CF set on error
	    AX = error code (03h,05h,06h,10h) (see #01680 at AH=59h/BX=0000h)
Notes:	directory must be empty (contain only '.' and '..' entries)
	under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
SeeAlso: AH=39h,AH=3Bh,AX=713Ah,AH=E2h/SF=0Bh,INT 2F/AX=1101h,INT 60/DI=0512h