ffmpeg: work around missing stdout flush in some cases (#26709)

See https://github.com/msys2/MINGW-packages/issues/26646#issuecomment-3599269090

mingw-w64-ffmpeg/0006-atexit-fflush.patch

@@ -0,0 +1,65 @@
+--- ffmpeg-8.0.1/fftools/cmdutils.c.orig	2025-12-04 12:02:39.048902000 +0100
++++ ffmpeg-8.0.1/fftools/cmdutils.c	2025-12-04 12:03:09.025919500 +0100
+@@ -72,6 +72,21 @@
+     vfprintf(stdout, fmt, vl);
+ }
+ 
++#if defined(_WIN32)
++static void
++exit_flush(void)
++{
++    fflush(NULL);
++}
++#endif
++
++void init_atexit(void)
++{
++#if defined(_WIN32)
++    atexit(exit_flush);
++#endif
++}
++
+ void init_dynload(void)
+ {
+ #if HAVE_SETDLLDIRECTORY && defined(_WIN32)
+--- ffmpeg-8.0.1/fftools/cmdutils.h.oriig	2025-12-04 12:03:14.817855900 +0100
++++ ffmpeg-8.0.1/fftools/cmdutils.h	2025-12-04 12:01:19.917757800 +0100
+@@ -54,6 +54,8 @@
+  */
+ void init_dynload(void);
+ 
++void init_atexit(void);
++
+ /**
+  * Uninitialize the cmdutils option system, in particular
+  * free the *_opts contexts and their contents.
+--- ffmpeg-8.0.1/fftools/ffmpeg.c.orig	2025-12-04 11:58:38.637191900 +0100
++++ ffmpeg-8.0.1/fftools/ffmpeg.c	2025-12-04 12:05:01.143673400 +0100
+@@ -968,6 +968,7 @@
+     int ret;
+     BenchmarkTimeStamps ti;
+ 
++    init_atexit();
+     init_dynload();
+ 
+     setvbuf(stderr,NULL,_IONBF,0); /* win32 runtime needs this */
+--- ffmpeg-8.0.1/fftools/ffplay.c.orig	2025-11-20 03:31:18.000000000 +0100
++++ ffmpeg-8.0.1/fftools/ffplay.c	2025-12-04 12:04:57.040537600 +0100
+@@ -3759,6 +3759,7 @@
+     int flags, ret;
+     VideoState *is;
+ 
++    init_atexit();
+     init_dynload();
+ 
+     av_log_set_flags(AV_LOG_SKIP_REPEATED);
+--- ffmpeg-8.0.1/fftools/ffprobe.c.orig	2025-11-20 03:31:18.000000000 +0100
++++ ffmpeg-8.0.1/fftools/ffprobe.c	2025-12-04 12:04:51.566511900 +0100
+@@ -3067,6 +3067,7 @@
+     char *f_name = NULL, *f_args = NULL;
+     int ret, input_ret, i;
+ 
++    init_atexit();
+     init_dynload();
+ 
+     setvbuf(stderr, NULL, _IONBF, 0); /* win32 runtime needs this */

mingw-w64-ffmpeg/PKGBUILD

@@ -7,7 +7,7 @@ _realname=ffmpeg
 pkgbase="mingw-w64-${_realname}"
 pkgname="${MINGW_PACKAGE_PREFIX}-${_realname}"
 pkgver=8.0.1
-pkgrel=1
+pkgrel=2
 pkgdesc="Complete solution to record, convert and stream audio and video (mingw-w64)"
 arch=('any')
 mingw_arch=('mingw32' 'mingw64' 'ucrt64' 'clang64' 'clangarm64')
@@ -79,13 +79,15 @@ makedepends=("${MINGW_PACKAGE_PREFIX}-cc"
 source=(https://ffmpeg.org/releases/${_realname}-${pkgver}.tar.xz{,.asc}
         "pathtools.c"
         "pathtools.h"
-        "0005-Win32-Add-path-relocation-to-frei0r-plugins-search.patch")
+        "0005-Win32-Add-path-relocation-to-frei0r-plugins-search.patch"
+        "0006-atexit-fflush.patch")
 validpgpkeys=('FCF986EA15E6E293A5644F10B4322F04D67658D8')
 sha256sums=('05ee0b03119b45c0bdb4df654b96802e909e0a752f72e4fe3794f487229e5a41'
             'SKIP'
             'ebf471173f5ee9c4416c10a78760cea8afaf1a4a6e653977321e8547ce7bf3c0'
             '1585ef1b61cf53a2ca27049c11d49e0834683dfda798f03547761375df482a90'
-            '8c74e9b5800dbb41c33a60114712726ec768ad6de8f147c2eb30656fd4c899cc')
+            '8c74e9b5800dbb41c33a60114712726ec768ad6de8f147c2eb30656fd4c899cc'
+            'd38cd99535300d8a37937ebad6e4dba6fe496bba6102d91794b29d94de4db7ed')
 
 # Helper macros to help make tasks easier #
 apply_patch_with_msg() {
@@ -107,6 +109,11 @@ prepare() {
 
   apply_patch_with_msg \
     0005-Win32-Add-path-relocation-to-frei0r-plugins-search.patch
+
+  # https://github.com/msys2/MINGW-packages/issues/26646
+  # Work around streams not being flushed on exit in some cases
+  apply_patch_with_msg \
+    0006-atexit-fflush.patch
 }
 
 build() {