This was breaking mpg123 if CFLAGS has -pedantic -Werror.
Refresh of the patch from:
https://lists.gnu.org/archive/html/libtool/2011-06/msg00040.html
_putenv is always __cdecl and is always dllimported from the OS C
runtime DLL.From 74bae2bbd96cf38eeda3495bedfcd7f5b90680fb Mon Sep 17 00:00:00 2001
From: Jonathan Yong <10wa...@gmail.com>
Date: Sun, 19 Mar 2023 12:03:33 +
Subject: [PATCH] libtool: fix long standing mingw _putenv warning
Fixes build if -Werror -pendantic is enabled in CFLAGS.
The MS specific _putenv in MinGW* will always be __cdecl and
will always be coming from the OS C runtime DLL, with no plans
for a static reimplementation.
Signed-off-by: Jonathan Yong <10wa...@gmail.com>
---
build-aux/ltmain.in | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/build-aux/ltmain.in b/build-aux/ltmain.in
index 3b76bd08..21330576 100644
--- a/build-aux/ltmain.in
+++ b/build-aux/ltmain.in
@@ -3662,7 +3662,8 @@ EOF
/* declarations of non-ANSI functions */
#if defined __MINGW32__
# ifdef __STRICT_ANSI__
-int _putenv (const char *);
+/* mingw _putenv is always from the C runtime DLL, and it is always __cdecl ABI */
+_CRTIMP int __cdecl _putenv (const char *);
# endif
#elif defined __CYGWIN__
# ifdef __STRICT_ANSI__
--
2.40.0