In debug output, show waitpid status with 6 hex digits, not 4

This shows event byte values better (without variable offset):

 [wait(0x01057f) = 29491] WIFSTOPPED,sig=SIGTRAP,EVENT_FORK (1)
 [wait(0x80057f) = 29492] WIFSTOPPED,sig=SIGTRAP,EVENT_STOP (128)
         ^^

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/strace.c b/strace.c
index 2741201..f5ce18d 100644
--- a/strace.c
+++ b/strace.c
@@ -2039,7 +2039,7 @@
 					e = "STOP";
 				sprintf(evbuf, ",EVENT_%s (%u)", e, event);
 			}
-			fprintf(stderr, " [wait(0x%04x) = %u] %s%s\n", status, pid, buf, evbuf);
+			fprintf(stderr, " [wait(0x%06x) = %u] %s%s\n", status, pid, buf, evbuf);
 		}
 
 		/* Look up 'pid' in our table. */