Add gcrypt downgrade patch

Restore-support-for-thread-callbacks-for-older-gcryp.patch

@@ -0,0 +1,94 @@
+From 43332a4fa12ff79f284749177dc0743a495caea6 Mon Sep 17 00:00:00 2001
+From: Nicolas Chauvet <kwizart@gmail.com>
+Date: Sat, 18 Jul 2020 15:19:31 +0200
+Subject: [PATCH 1/1] Restore support for thread callbacks for older gcrypt
+
+---
+ include/vlc_gcrypt.h | 64 ++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 64 insertions(+)
+
+diff --git a/include/vlc_gcrypt.h b/include/vlc_gcrypt.h
+index a04e1b1d86..4c7f1e86b0 100644
+--- a/include/vlc_gcrypt.h
++++ b/include/vlc_gcrypt.h
+@@ -25,6 +25,67 @@
+ 
+ #include <errno.h>
+ 
++#if GCRYPT_VERSION_NUMBER < 0x010600
++#ifdef LIBVLC_USE_PTHREAD
++/**
++ * If possible, use gcrypt-provided thread implementation. This is so that
++ * other non-VLC components (inside the process) can also use gcrypt safely.
++ */
++GCRY_THREAD_OPTION_PTHREAD_IMPL;
++# define gcry_threads_vlc gcry_threads_pthread
++#else
++
++/**
++ * gcrypt thread option VLC implementation
++ */
++
++static int gcry_vlc_mutex_init( void **p_sys )
++{
++    vlc_mutex_t *p_lock = (vlc_mutex_t *)malloc( sizeof( vlc_mutex_t ) );
++    if( p_lock == NULL)
++        return ENOMEM;
++
++    vlc_mutex_init( p_lock );
++    *p_sys = p_lock;
++    return VLC_SUCCESS;
++}
++
++static int gcry_vlc_mutex_destroy( void **p_sys )
++{
++    vlc_mutex_t *p_lock = (vlc_mutex_t *)*p_sys;
++    vlc_mutex_destroy( p_lock );
++    free( p_lock );
++    return VLC_SUCCESS;
++}
++
++static int gcry_vlc_mutex_lock( void **p_sys )
++{
++    vlc_mutex_lock( (vlc_mutex_t *)*p_sys );
++    return VLC_SUCCESS;
++}
++
++static int gcry_vlc_mutex_unlock( void **lock )
++{
++    vlc_mutex_unlock( (vlc_mutex_t *)*lock );
++    return VLC_SUCCESS;
++}
++
++static const struct gcry_thread_cbs gcry_threads_vlc =
++{
++    GCRY_THREAD_OPTION_USER,
++    NULL,
++    gcry_vlc_mutex_init,
++    gcry_vlc_mutex_destroy,
++    gcry_vlc_mutex_lock,
++    gcry_vlc_mutex_unlock,
++    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
++};
++#endif
++#endif
++
++/**
++ * Initializes gcrypt with proper locking.
++ */
+ static inline void vlc_gcrypt_init (void)
+ {
+     /* This would need a process-wide static mutex with all libraries linking
+@@ -37,6 +98,9 @@ static inline void vlc_gcrypt_init (void)
+     vlc_global_lock (VLC_GCRYPT_MUTEX);
+     if (!done)
+     {
++#if GCRYPT_VERSION_NUMBER < 0x010600
++        gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_vlc);
++#endif
+         /* The suggested way for an application to make sure that global_init
+          * has been called is by using gcry_check_version. (see global_init
+          * comments in gcrypt sources) */
+-- 
+2.25.4
+