IX = DOR handle
OUT, if call successful:
Fc = 0
IX = 0, DOR handle deleted.
OUT, if call failed:
Fc = 1
IX = 0
A = RC_???
Registers changed after return:
Internal operating system usage. Applications must use GN_Del.
GN_Cl, close file
GN_Del, delete a file from memory
GN_Opf, open file/resource (wildcard search)
GN_Ren, rename file
OS_Cl, internal close (OZ usage)
OS_Frm, file read miscellaneous
OS_Fwm, file write miscellaneous
OS_Gb, get byte from file (or device)
OS_Gbt, get byte from file (or device) with timeout
OS_Mv, move bytes between stream and memory
OS_Op, internal open (OZ sage)
OS_Pb, write byte to file, device
OS_Pbt, write byte to file, device with timeout
OS_Ren, file rename (internal OZ usage)