From 395f925941da7b9d8527b8ec218ecc596799ffd6 Mon Sep 17 00:00:00 2001
From: Rob Loach <robloach@gmail.com>
Date: Thu, 16 May 2024 16:05:58 -0400
Subject: [PATCH] libretro-common: Fix redefinition warnings of _POSIX_C_SOURCE
 (#15748)

Small fix to only define `_POSIX_C_SOURCE` if it's not already defined.

```
rthreads/rthreads.c:25: warning: "_POSIX_C_SOURCE" redefined
```
---
 libretro-common/rthreads/rthreads.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libretro-common/rthreads/rthreads.c b/libretro-common/rthreads/rthreads.c
index ff11978668..2a748edd53 100644
--- a/libretro-common/rthreads/rthreads.c
+++ b/libretro-common/rthreads/rthreads.c
@@ -22,9 +22,11 @@
 
 #ifdef __unix__
 #ifndef __sun__
+#ifndef _POSIX_C_SOURCE
 #define _POSIX_C_SOURCE 199309
 #endif
 #endif
+#endif
 
 #include <stdlib.h>
 #include <string.h>