Deanon: merge the Biobufhdr into Biobuf

I'm leaving all uses of Biobufhdr intact in case somehow has some other way
to do this. This change is critical to the deanon effort.

Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>

sys/include/bio.h

@@ -11,7 +11,7 @@
 #pragma	lib	"libbio.a"
 
 typedef	struct	Biobuf	Biobuf;
-typedef	struct	Biobufhdr	Biobufhdr;
+typedef	struct	Biobuf	Biobufhdr;
 
 enum
 {
@@ -27,7 +27,7 @@ enum
 	Bracteof,
 };
 
-struct	Biobufhdr
+struct	Biobuf
 {
 	int	icount;		/* neg num of bytes at eob */
 	int	ocount;		/* num of bytes at bob */
@@ -41,11 +41,6 @@ struct	Biobufhdr
 	uint8_t*	bbuf;		/* pointer to beginning of buffer */
 	uint8_t*	ebuf;		/* pointer to end of buffer */
 	uint8_t*	gbuf;		/* pointer to good data in buf */
-};
-
-struct	Biobuf
-{
-	Biobufhdr;
 	uint8_t	b[Bungetsize+Bsize];
 };