Use open-vcdiff source in its new home on the Mac (follow-up to r2709)

sdch/sdch.xcodeproj/sdch_prebuild.sh

 #!/bin/sh
 
 # Copyright (c) 2008 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.
 
 set -ex
 
 GENERATED_DIR="${CONFIGURATION_TEMP_DIR}/generated"
 
 # Generate config.h the same way that "sh configure" would
 mkdir -p "${GENERATED_DIR}"
 
 CONFIG_H_IN="$1"
 if test "X${CONFIG_H_IN}" = "X"; then
-  CONFIG_H_IN="open_vcdiff/depot/opensource/open-vcdiff/src/config.h.in"
+  CONFIG_H_IN="open-vcdiff/src/config.h.in"
 fi
 
 CONFIG_H="${GENERATED_DIR}/config.h"
 sed -e s/'^#undef HAVE_DLFCN_H$'/'#define HAVE_DLFCN_H 1'/ \
     -e s/'^#undef HAVE_FNMATCH_H$'/'#define HAVE_FNMATCH_H 1'/ \
     -e s/'^#undef HAVE_GETOPT_H$'/'#define HAVE_GETOPT_H 1'/ \
     -e s/'^#undef HAVE_GETTIMEOFDAY$'/'#define HAVE_GETTIMEOFDAY 1'/ \
     -e s/'^#undef HAVE_INTTYPES_H$'/'#define HAVE_INTTYPES_H 1'/ \
     -e s/'^#undef HAVE_MEMORY_H$'/'#define HAVE_MEMORY_H 1'/ \
     -e s/'^#undef HAVE_MPROTECT$'/'#define HAVE_MPROTECT 1'/ \
@@ skipping 23 matching lines @@
     -e s/'^#undef VERSION$'/'#define VERSION "0.1"'/ \
     -e s@'^\(#undef .*\)$'@'/* \1 */'@ \
   < "${CONFIG_H_IN}" \
   > "${CONFIG_H}.new"
 
 if ! diff -q "${CONFIG_H}.new" "${CONFIG_H}" >& /dev/null ; then
   mv "${CONFIG_H}.new" "${CONFIG_H}"
 else
   rm "${CONFIG_H}.new"
 fi