[-] Fix deprecated GCRY_THREAD_OPTION_PTHREAD_IMPL and GCRYCTL_SET_THREAD_CBS

Looks like libgcrypt uses platform standard threading instead of asking caller
for a threading package/callbacks.

configure.ac

@@ -171,7 +171,7 @@ PKG_CHECK_EXISTS([libplist],
 	[OWNTONE_MODULES_CHECK([OWNTONE], [LIBPLIST], [libplist-2.0],
 		[plist_dict_get_item], [plist/plist.h])])
 
-AM_PATH_LIBGCRYPT([1:1.2.0])
+AM_PATH_LIBGCRYPT([1:1.7.0])
 OWNTONE_FUNC_REQUIRE([OWNTONE], [GNU Crypt Library], [LIBGCRYPT], [gcrypt],
 	[gcry_control], [gcrypt.h])
 AM_PATH_GPG_ERROR([1.6])

src/main.c

@@ -58,7 +58,6 @@
 
 #include <pthread.h>
 #include <gcrypt.h>
-GCRY_THREAD_OPTION_PTHREAD_IMPL;
 
 #include "conffile.h"
 #include "db.h"
@@ -684,9 +683,6 @@ main(int argc, char **argv)
   /* Initialize libcurl */
   curl_global_init(CURL_GLOBAL_DEFAULT);
 
-  /* Initialize libgcrypt */
-  gcry_control(GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
-
   gcry_version = gcry_check_version(GCRYPT_VERSION);
   if (!gcry_version)
     {