compel/log: Provide %u specifier parsing

%u is quite common and I remember there were workarounds to print
(unsigned long) as long or whatever.
Just support it from now - it's not hard and not much code.

Signed-off-by: Dmitry Safonov <dima@arista.com>

compel/plugins/std/log.c

@@ -225,6 +225,22 @@ static void print_num_l(long num, struct simple_buf *b)
 	print_string(s, b);
 }
 
+static void print_num_u(unsigned long num, struct simple_buf *b)
+{
+	char buf[22], *s;
+
+	buf[21] = '\0';
+	s = &buf[21];
+
+	do {
+		s--;
+		*s = (num % 10) + '0';
+		num /= 10;
+	} while (num > 0);
+
+	print_string(s, b);
+}
+
 static void hexdigit(unsigned int v, char *to, char **z)
 {
 	*to = "0123456789abcdef"[v & 0xf];
@@ -329,6 +345,12 @@ static void sbuf_printf(struct simple_buf *b, const char *format, va_list args)
 		case 'p':
 			print_hex_l((unsigned long)va_arg(args, void *), b);
 			break;
+		case 'u':
+			if (along)
+				print_num_u(va_arg(args, unsigned long), b);
+			else
+				print_num_u(va_arg(args, unsigned), b);
+			break;
 		default:
 			print_string("\nError: Unknown printf format %", b);
 			sbuf_putc(b, *s);