From 8c5c74b2f1a4e1a5f3e16c3ca18ae449faf65d96 Mon Sep 17 00:00:00 2001
From: Ben Barham <ben_barham@apple.com>
Date: Fri, 26 Jan 2024 11:19:32 -0800
Subject: [PATCH] Add define for GNU glibc extensions

`fdopen`, `strdup`, and `mkstemp` are all extensions. `_DEFAULT_SOURCE`
should be enough for this, but apparently not on older glibcs.
---
 api_test/harness.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/api_test/harness.c b/api_test/harness.c
index 6b7336f97..f561aeace 100644
--- a/api_test/harness.c
+++ b/api_test/harness.c
@@ -1,4 +1,7 @@
-#define _DEFAULT_SOURCE
+// _GNU_SOURCE is all ISO/POSIX/XOPEN/BSD/SVID + GNU extensions. It also sets
+// _DEFAULT_SOURCE on newer glibc. We need this for strdup/snprintf/fdopen/etc.
+#define _GNU_SOURCE
+
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>