INT 21 - DOS 2+ - "UNLINK" - DELETE FILE
	AH = 41h
	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. filename (no wildcards, but see notes)
	CL = attribute mask for deletion (server call only, see notes)
Return: CF clear if successful
	    AX destroyed (DOS 3.3) AL seems to be drive of deleted file
	CF set on error
	    AX = error code (02h,03h,05h) (see #01680 at AH=59h/BX=0000h)
Notes:	(DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case
	  the filespec must be canonical (as returned by AH=60h), and only
	  files matching the attribute mask in CL are deleted
	DR DOS 5.0-6.0 returns error code 03h if invoked via AX=5D00h; DR DOS
	  3.41 crashes if called via AX=5D00h with wildcards
	DOS does not erase the file's data; it merely becomes inaccessible
	  because the FATsee File Allocation Table chain for the file is cleared
	deleting a file which is currently open may lead to filesystem
	  corruption.  Unless SHARE is loaded, DOS does not close the handles
	  referencing the deleted file, thus allowing writes to a nonexistant
	  file.
	under DR DOS and DR Multiuser DOS, this function will fail if the file
	  is currently open
	under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
BUG:	DR DOS 3.41 crashes if called via AX=5D00h
SeeAlso: AH=13h,AX=4301h,AX=4380h,AX=5D00h,AH=60h,AX=7141h,AX=F244h
SeeAlso: INT 2F/AX=1113h