SDL_mixer: libtool upgrade to 2.4.6 - 8/n: set file_list_spec to '@' on OS/2

https://github.com/libsdl-org/SDL_mixer/commit/3dda671a1517803b2cecc261ba29a0f2462c7fe3

From 3dda671a1517803b2cecc261ba29a0f2462c7fe3 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Thu, 2 Dec 2021 20:50:10 +0300
Subject: [PATCH] libtool upgrade to 2.4.6 - 8/n: set file_list_spec to '@' on
 OS/2

http://git.savannah.gnu.org/gitweb/?p=libtool.git;a=commitdiff;h=a938703c462bd2ba0e520808d45186020ea600be
---
 acinclude/libtool.m4 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/acinclude/libtool.m4 b/acinclude/libtool.m4
index 16c5f584..290d0304 100644
--- a/acinclude/libtool.m4
+++ b/acinclude/libtool.m4
@@ -5151,6 +5151,7 @@ _LT_EOF
 	emximp -o $lib $output_objdir/$libname.def'
       _LT_TAGVAR(old_archive_from_new_cmds, $1)='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
       _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+      _LT_TAGVAR(file_list_spec, $1)='@'
       ;;
 
     interix[[3-9]]*)
@@ -5856,6 +5857,7 @@ _LT_EOF
 	emximp -o $lib $output_objdir/$libname.def'
       _LT_TAGVAR(old_archive_from_new_cmds, $1)='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
       _LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+      _LT_TAGVAR(file_list_spec, $1)='@'
       ;;
 
     osf3*)
@@ -6725,6 +6727,7 @@ if test yes != "$_lt_caught_CXX_error"; then
 	  emximp -o $lib $output_objdir/$libname.def'
 	_LT_TAGVAR(old_archive_from_new_cmds, $1)='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
 	_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
+	_LT_TAGVAR(file_list_spec, $1)='@'
 	;;
 
       dgux*)