use ASN1_TIME_to_tm for openssl-4
See https://bugs.gentoo.org/984953
--- a/src/tlsopensslbase.cpp
+++ b/src/tlsopensslbase.cpp
@@ -224,38 +224,11 @@ namespace gloox
   int OpenSSLBase::ASN1Time2UnixTime( ASN1_TIME* time )
   {
     struct tm t;
-    const char* str = reinterpret_cast<const char*>( time->data );
-    size_t i = 0;
 
     memset( &t, 0, sizeof(t) );
 
-    if( time->type == V_ASN1_UTCTIME ) /* two digit year */
-    {
-      t.tm_year = ( str[i++] - '0' ) * 10;
-      t.tm_year += ( str[i++] - '0' );
-
-      if( t.tm_year < 70 )
-        t.tm_year += 100;
-    }
-    else if( time->type == V_ASN1_GENERALIZEDTIME ) /* four digit year */
-    {
-      t.tm_year = ( str[i++] - '0' ) * 1000;
-      t.tm_year += ( str[i++] - '0' ) * 100;
-      t.tm_year += ( str[i++] - '0' ) * 10;
-      t.tm_year += ( str[i++] - '0' );
-      t.tm_year -= 1900;
-    }
-
-    t.tm_mon = ( str[i++] - '0' ) * 10;
-    t.tm_mon += ( str[i++] - '0' ) - 1; // -1 since January is 0 not 1.
-    t.tm_mday = ( str[i++] - '0' ) * 10;
-    t.tm_mday += ( str[i++] - '0' );
-    t.tm_hour = ( str[i++] - '0' ) * 10;
-    t.tm_hour += ( str[i++] - '0' );
-    t.tm_min = ( str[i++] - '0' ) * 10;
-    t.tm_min += ( str[i++] - '0' );
-    t.tm_sec = ( str[i++] - '0' ) * 10;
-    t.tm_sec += ( str[i++] - '0' );
+    if( !ASN1_TIME_to_tm( time, &t ) )
+      return -1;
 
     return static_cast<int>( mktime( &t ) );
   }