printf: handle \0 in %b arguments

The %b case was using fputs after unescape to print the argument, which
meant that it could not handle nul bytes. Instead, store the length
returned from unescape and use fwrite to properly handle them.

printf.c

@@ -19,7 +19,7 @@ int
 main(int argc, char *argv[])
 {
 	Rune *rarg;
-	size_t i, j, argi, lastargi, formatlen;
+	size_t i, j, argi, lastargi, formatlen, blen;
 	long long num;
 	double dou;
 	int cooldown = 0, width, precision, ret = 0;
@@ -112,12 +112,12 @@ main(int argc, char *argv[])
 		case 'b':
 			if ((tmp = strstr(arg, "\\c"))) {
 				*tmp = 0;
-				unescape(arg);
-				fputs(arg, stdout);
+				blen = unescape(arg);
+				fwrite(arg, sizeof(*arg), blen, stdout);
 				return 0;
 			}
-			unescape(arg);
-			fputs(arg, stdout);
+			blen = unescape(arg);
+			fwrite(arg, sizeof(*arg), blen, stdout);
 			break;
 		case 'c':
 			unescape(arg);