[2497] Add placeholder MasterLoader class

It just contains MasterLoader::Options enum for now.

src/lib/dns/Makefile.am

@@ -120,6 +120,7 @@ libb10_dns___la_SOURCES += tsigkey.h tsigkey.cc
 libb10_dns___la_SOURCES += tsigrecord.h tsigrecord.cc
 libb10_dns___la_SOURCES += character_string.h character_string.cc
 libb10_dns___la_SOURCES += master_loader_callbacks.h
+libb10_dns___la_SOURCES += master_loader.h
 libb10_dns___la_SOURCES += rdata/generic/detail/nsec_bitmap.h
 libb10_dns___la_SOURCES += rdata/generic/detail/nsec_bitmap.cc
 libb10_dns___la_SOURCES += rdata/generic/detail/nsec3param_common.cc

src/lib/dns/master_loader.h

@@ -0,0 +1,34 @@
+// Copyright (C) 2012  Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#ifndef MASTER_LOADER_H
+#define MASTER_LOADER_H
+
+namespace isc {
+namespace dns {
+
+// Placeholder introduced by #2497. The real class should be updated in
+// #2377.
+class MasterLoader {
+public:
+    enum Options {
+         MANY_ERRORS, // lenient mode
+         // also eventually some check policies like "check NS name"
+    };
+};
+
+}
+}
+
+#endif // MASTER_LOADER_H