[PATCH] lib/stdio.in.h: define _POSIX_C_SOURCE on >=Sierra

[Sevan Janiyan]

Hello,

Attached patch fixes build on OS X 10.4.
Defining _POSIX_C_SOURCE has the undesired effect there, causing issues 
with missing type definitions to completely unrelated components 
(including more headers is not the correct solution).

SevanFrom d5b35116fb7b58dab97d12f4d32ff9d45b1fb508 Mon Sep 17 00:00:00 2001
From: Sevan Janiyan <ventur...@geeklan.co.uk>
Date: Tue, 7 Nov 2023 20:19:56 +0000
Subject: [PATCH] lib/stdio.in.h: define _POSIX_C_SOURCE on >=Sierra

200809L support was added in macOS Lion 10.7.
sprintf and vsprintf were deprecated in macOS Sierra 10.12.
On OS X Tiger 10.4, defining _POSIX_C_SOURCE has the undesired effect, resulting
in build failure. Use AvailabilityMacros.h & guard off the definition to when
building on macOS 10.12 or newer.
---
 lib/stdio.in.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/stdio.in.h b/lib/stdio.in.h
index 118874d877..0165fbb15c 100644
--- a/lib/stdio.in.h
+++ b/lib/stdio.in.h
@@ -38,8 +38,11 @@
 
 /* Suppress macOS deprecation warnings for sprintf and vsprintf.  */
 #if (defined __APPLE__ && defined __MACH__) && !defined _POSIX_C_SOURCE
+# include <AvailabilityMacros.h>
+# if defined(MAC_OS_X_VERSION_MIN_REQUIRED) && MAC_OS_X_VERSION_MIN_REQUIRED 
>= 101200
 # define _POSIX_C_SOURCE 200809L
 # define _GL_DEFINED__POSIX_C_SOURCE
+# endif
 #endif
 
 #define _GL_ALREADY_INCLUDING_STDIO_H
-- 
2.41.0