gnutls: remove gcrypt initialization

There are no (other) reasons for the GnuTLS plugin to link against
libgcrypt. Since nettle has been the default back-end for GnuTLS for
ages, this old code has become more harmful than good.

Besides, this code was not sufficient to really address the thread
safety issues in libgcrypt (since it is also used via other paths).

configure.ac

@@ -3799,13 +3799,6 @@ dnl TLS/SSL
 dnl
 AC_ARG_ENABLE(gnutls,
   [  --enable-gnutls         GNU TLS TLS/SSL support (default enabled)])
-
-AS_IF([test "${have_libgcrypt}" != "yes"], [
-  AS_IF([test "${enable_gnutls}" = "yes"], [
-    AC_MSG_ERROR([--enable-gnutls and --disable-libgcrypt are mutually exclusive.])
-  ])
-  enable_gnutls="no"
-])
 AS_IF([test "${enable_gnutls}" != "no"], [
   PKG_CHECK_MODULES(GNUTLS, [gnutls >= 2.6.6], [
     VLC_ADD_PLUGIN([gnutls])

modules/misc/Modules.am

@@ -13,8 +13,8 @@ libexport_plugin_la_LIBADD = $(AM_LIBADD)
 libvlc_LTLIBRARIES += libexport_plugin.la
 
 libgnutls_plugin_la_SOURCES = gnutls.c dhparams.h
-libgnutls_plugin_la_CFLAGS = $(AM_CFLAGS) $(GNUTLS_CFLAGS) $(GCRYPT_CFLAGS)
-libgnutls_plugin_la_LIBADD = $(AM_LIBADD) $(GNUTLS_LIBS) $(GCRYPT_LIBS)
+libgnutls_plugin_la_CFLAGS = $(AM_CFLAGS) $(GNUTLS_CFLAGS)
+libgnutls_plugin_la_LIBADD = $(AM_LIBADD) $(GNUTLS_LIBS)
 if HAVE_WIN32
 libgnutls_plugin_la_LIBADD += -lcrypt32 $(SOCKET_LIBS)
 endif

modules/misc/gnutls.c

@@ -47,11 +47,9 @@
 #include <vlc_fs.h>
 #include <vlc_block.h>
 
-#include <gcrypt.h>
 #include <gnutls/gnutls.h>
 #include <gnutls/x509.h>
 
-#include <vlc_gcrypt.h>
 #include "dhparams.h"
 
 #include <assert.h>
@@ -113,8 +111,6 @@ static int gnutls_Init (vlc_object_t *p_this)
 {
     int ret = VLC_EGENERIC;
 
-    vlc_gcrypt_init (); /* GnuTLS depends on gcrypt */
-
     vlc_mutex_lock (&gnutls_mutex);
     if (gnutls_global_init ())
     {