Revert r310138

Adding %b support to vfprintf for parity with kernel space requires
more discussion/review.

In particular, many parties were concerned over introducing a
non-standard format qualifier to *printf(3) which didn't already
exist in other OSes, e.g. Linux, thus making code which used %b
harder to port to other operating systems.

Requested by:	many

lib/libc/stdio/vfprintf.c

@@ -611,37 +611,6 @@ reswitch:	switch (ch) {
 		case 'z':
 			flags |= SIZET;
 			goto rflag;
-		case 'b':
-			{
-			const char *q;
-			int anybitset, bit;
-
-			ulval = (u_int)GETARG(int);
-			cp = GETARG(char *);
-
-			q = __ultoa(ulval, buf + BUF, *cp++, 0, xdigs_lower);
-			PRINT(q, buf + BUF - q);
-
-			if (ulval == 0)
-				break;
-
-			for (anybitset = 0; *cp;) {
-				bit = *cp++;
-				if (ulval & (1 << (bit - 1))) {
-					PRINT(anybitset ? "," : "<", 1);
-					q = cp;
-					for (; (bit = *cp) > ' '; ++cp)
-						continue;
-					PRINT(q, cp - q);
-					anybitset = 1;
-				} else
-					for (; *cp > ' '; ++cp)
-						continue;
-			}
-			if (anybitset)
-				PRINT(">", 1);
-			}
-			continue;
 		case 'C':
 			flags |= LONGINT;
 			/*FALLTHROUGH*/