Add _krb5_log() used for internal logging

lib/krb5/log.c

@@ -488,3 +488,19 @@ krb5_log(krb5_context context,
     return ret;
 }
 
+void KRB5_LIB_FUNCTION
+_krb5_debug(krb5_context context,
+	    int level,
+	    const char *fmt,
+	    ...)
+    __attribute__((format (printf, 3, 4)))
+{
+    va_list ap;
+
+    if (context == NULL || context->debug_dest == NULL)
+	return;
+	
+    va_start(ap, fmt);
+    krb5_vlog(context, context->debug_dest, level, fmt, ap);
+    va_end(ap);
+}