stop using non-standard macro, use WEXITSTATUS instead

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/runit/runsv.c b/runit/runsv.c
index 6d34dc1..5cb5d2f 100644
--- a/runit/runsv.c
+++ b/runit/runsv.c
@@ -252,7 +252,8 @@
 	char a[10];
 	struct stat st;
 
-	if (s->islog) return 0;
+	if (s->islog)
+		return 0;
 	strcpy(a, "control/?");
 	a[8] = c; /* replace '?' */
 	if (stat(a, &st) == 0) {
@@ -274,7 +275,7 @@
 				warn_cannot("wait for child control/?");
 				return 0;
 			}
-			return !wait_exitcode(w);
+			return WEXITSTATUS(w) == 0;
 		}
 	} else {
 		if (errno != ENOENT)