From a0771d15e67d3fe6ac1791f81d9731f73c550e5e Mon Sep 17 00:00:00 2001
From: Jonas Nick <jonasd.nick@gmail.com>
Date: Mon, 25 Nov 2019 10:17:02 +0000
Subject: [PATCH] Explicitly disable buffering for stderr in tests

---
 src/tests.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/tests.c b/src/tests.c
index 35fc8adb72700..d1cfcb5d03ed5 100644
--- a/src/tests.c
+++ b/src/tests.c
@@ -5174,6 +5174,9 @@ int main(int argc, char **argv) {
      * diagnostic information. Happens right at the start of main because
      * setbuf must be used before any other operation on the stream. */
     setbuf(stdout, NULL);
+    /* Also disable buffering for stderr because it's not guaranteed that it's
+     * unbuffered on all systems. */
+    setbuf(stderr, NULL);
 
     /* find iteration count */
     if (argc > 1) {