Disable various unused libxml features: catalogs, DocBook, legacy APIs, etc.

testing/libfuzzer/fuzzers/libxml_xml_regexp_compile_fuzzer.cc

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include <algorithm>
-#include <string>
-#include <vector>
-
-#include "libxml/parser.h"
-#include "libxml/tree.h"
-#include "libxml/xmlversion.h"
-
-
-void ignore (void * ctx, const char * msg, ...) {
-  // Error handler to avoid spam of error messages from libxml parser.
-}
-
-
-// Entry point for LibFuzzer.
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
-  xmlSetGenericErrorFunc(NULL, &ignore);
-
-  std::vector<uint8_t> buffer(size + 1, 0);
-  std::copy(data, data + size, buffer.data());
-
-  xmlRegexpPtr x = xmlRegexpCompile(buffer.data());
-  if (x)
-    xmlRegFreeRegexp(x);
-
-  return 0;
-}