GN_Dir, Create a directory path

Register parameters

RST 20H, DEFW $8809

IN:     BHL = pointer to null-terminated directory path name

out, if successful:
        Fc = 0, directory successfully created

out, if failed:
        Fc = 1, unable to create directory
        A = error code:
             RC_IVF, Invalid directory path name
             RC_USE, Directory in use
             RC_EXIS, Directory already exists

   registers changed after return:
        A.BCDEHL/IXIY  same
        .F....../....  different

Notes

API call implemented in OZ 5.0
Several sub-directories are accepted (eg. :RAM.0/dir1/dir2/dir3 ) up to 205 characters
Only accept explicit filenames (wildcard are not allowed)
However, if a RAM device is not specified, it will automatically be included (the current) into the directory name.
The buffer of the directory name must have space enough to get itself expanded with a device name (additional 6 bytes).
The filename must be terminated by a control character, eg. null (0) or CR (13).

Related calls

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_Del, file delete (internal 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 usage)
OS_Pb, write byte to file, device
OS_Pbt, write byte to file, device with timeout
OS_Ren, file rename (internal OZ usage)