multimedia/ffmpeg: fix symbol versioning problem on stable/14

Preamble: I made this change a while ago but couldn't find time to share it.
Now I see that ffmpeg 8 is in the works, so maybe I am too late or, at least, 
the change will need some rework.
The change addresses an issue similar to 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=284651 and multiple others.

commit 7f9d8df0bafbb3ffbe0399a28b8d232bb2c58612
Author:     Andriy Gapon <avg@FreeBSD.org>
AuthorDate: Sat Jun 21 17:16:33 2025 +0300
Commit:     Andriy Gapon <avg@FreeBSD.org>
CommitDate: Sat Sep 6 15:47:50 2025 +0300

     multimedia/ffmpeg: fix symbol versioning problem on stable/14

     This is a well-known issue related to visibility of environ and __progname
     symbols from /usr/lib/crt1.o.

     This change patches configure to give those symbols global visibility
     when testing --version-script support.
     Otherwise, the port would produce broken libraries without symbol versions.

     This change also adds HAS_SYMBOL_VERSION to catch the problem using
     libavcodec.so as a canary.

diff --git a/multimedia/ffmpeg/Makefile b/multimedia/ffmpeg/Makefile
index f7c5d80adeac..fd25b9238021 100644
--- a/multimedia/ffmpeg/Makefile
+++ b/multimedia/ffmpeg/Makefile
@@ -28,6 +28,7 @@ USE_PERL5=	build
  SHEBANG_FILES=	doc/texi2pod.pl
  NOPRECIOUSMAKEVARS=	yes # ARCH

+HAS_SYMBOL_VERSION=	${PREFIX}/lib/libavcodec.so
  PORTSCOUT=	limit:^6\.

  # Option CHROMAPRINT disabled, it cannot work and people are baffled.
diff --git a/multimedia/ffmpeg/files/patch-configure 
b/multimedia/ffmpeg/files/patch-configure
index 9654237228cc..c3a166b984ca 100644
--- a/multimedia/ffmpeg/files/patch-configure
+++ b/multimedia/ffmpeg/files/patch-configure
@@ -28,3 +28,12 @@
                               -lSPVRemapper -lSPIRV -lSPIRV-Tools-opt 
-lSPIRV-Tools -lpthread -lstdc++ -lm; }
   enabled libgme            && { check_pkg_config libgme libgme gme/gme.h 
gme_new_emu ||
                                  require libgme gme/gme.h gme_new_emu -lgme 
-lstdc++; }
+@@ -7307,7 +7301,7 @@
+ EOF
+
+ if enabled proper_dce; then
+-    echo "X { local: *; };" > $TMPV
++    echo "X { global: environ; __progname; local: *; };" > $TMPV
+     if test_ldflags -Wl,${version_script},$TMPV; then
+         append SHFLAGS '-Wl,${version_script},\$(SUBDIR)lib\$(NAME).ver'
+         quotes='""'



-- 
Andriy Gapon