Add top level build script for building packages.

ports/gmock/build.sh

 #!/bin/bash
 # Copyright (c) 2011 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source pkg_info
-source ../../build_tools/common.sh
 
 ConfigureStep() {
   Banner "Configuring ${PACKAGE_NAME}"
   # export the nacl tools
   export CC=${NACLCC}
   export CXX=${NACLCXX}
   export AR=${NACLAR}
   export RANLIB=${NACLRANLIB}
   export PATH=${NACL_BIN_PATH}:${PATH};
   export LIB_GMOCK=libgmock.a
 
   ChangeDir ${NACL_PACKAGES_REPOSITORY}/${PACKAGE_NAME}
 }
 
 
 InstallStep() {
   Remove ${NACLPORTS_INCLUDE}/gmock
   readonly THIS_PACKAGE_PATH=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_NAME}
   (ChangeDir include; tar cf - gmock | (ChangeDir ${NACLPORTS_INCLUDE}; tar xfp -))
   Remove ${NACLPORTS_LIBDIR}/${LIB_GMOCK}
   install -m 644 ${LIB_GMOCK} ${NACLPORTS_LIBDIR}/${LIB_GMOCK}
 }
-
-
-PackageInstall
-exit 0