From 7b157815ab4222c30e7a4fb682735cf91d031da1 Mon Sep 17 00:00:00 2001
From: David Reid <mackron@gmail.com>
Date: Thu, 17 Jul 2025 15:08:58 +1000
Subject: [PATCH] Fix ALSA build on very old compilers.

---
 miniaudio.h | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/miniaudio.h b/miniaudio.h
index 05bc8e7a..f5215182 100644
--- a/miniaudio.h
+++ b/miniaudio.h
@@ -28165,7 +28165,19 @@ ma_device_backend_vtable* ma_device_backend_winmm = NULL;
 ALSA Backend
 
 ******************************************************************************/
-#ifdef MA_HAS_ALSA
+/*
+Our ALSA backend uses poll() and eventfd() which are not available on very old
+versions of Linux so we'll need check for it and disable the ALSA backend if
+necessary. This should be a non-issue in practice because ALSA itself won't be
+available in old versions of Linux anyway.
+*/
+#if defined(MA_HAS_ALSA)
+    #if (!defined(_POSIX_C_SOURCE) || _POSIX_C_SOURCE < 199309L)
+        #undef MA_HAS_ALSA
+    #endif
+#endif
+
+#if defined(MA_HAS_ALSA)
 
 #include <poll.h>           /* poll(), struct pollfd */
 #include <sys/eventfd.h>    /* eventfd() */