From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Date: Thu, 17 Sep 2015 05:39:56 -0400
Subject: let a failed diff be verbose

there is no reason to pass -q to diff when comparing output: if diff
succeeds, it will be quiet.  If it fails, the test fails, and so we
want it in our stderr!
---
 test/runtests | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/runtests b/test/runtests
index bf172ec..1957168 100755
--- a/test/runtests
+++ b/test/runtests
@@ -207,7 +207,7 @@ for t in $tests; do
     unset sleep_pidfile
 
     if [ -e ${t}/output ] ; then
-	diff_output_filter_headers "${t}/output" "$output" "-q"
+	diff_output_filter_headers "${t}/output" "$output" >&2
     fi
     if [ -n "${USE_MSVA}" ]; then
 	trap stop_msva EXIT