TC: int findnext( struct ffblk *ffblk )

	  MSC: unsigned _dos_findnext( struct find_t *fileinfo )

	- prototype in dir.h, also include  (MSC: dos.h only)

	- findnext updates DTA
	- returns 0 if OK, -1 if no matching files found or on error
	- gets next disk directory via DOS 0x4F, after calling findfirst()
	- struct ffblk is defined in dir.h for Turbo C and dos.h for MSC

	struct ffblk	(Turbo C)	struct find_t	(MSC)
	    {				    {
	    char     ff_reserved[21];	    char     reserved[21];
	    char     ff_attrib; 	    char     attrib;
	    unsigned ff_ftime;		    unsigned wr_time;
	    unsigned ff_fdate;		    unsigned wr_date;
	    long     ff_fsize;		    long     size;
	    char     ff_name[13];	    char     name[13];
	    };				    };

	- normal files are always included along with files that match
	  the requested attributes except when the LABEL attribute is
	  requested.  It's up to the programmer to determine which
	  actually match the requested attributes.
	- see	FILE ATTRIBUTES,  findfirst(), getdta(), setdta()