Add top level build script for building packages.

ports/DevIL/build.sh

 #!/bin/bash
 # Copyright (c) 2013 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
 
 TestStep() {
   return 0
   Banner "Testing ${PACKAGE_NAME}"
 
   if [ ${NACL_ARCH} == "pnacl" ]; then
     # Run once for each architecture.
     local pexe=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}/${NACL_BUILD_SUBDIR}/test/testil
     local script=${pexe}.sh
 
     TranslateAndWriteSelLdrScript ${pexe} x86-32 ${pexe}.x86-32.nexe ${script}
     cd ${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}/${NACL_BUILD_SUBDIR}/test && make check
 
     TranslateAndWriteSelLdrScript ${pexe} x86-64 ${pexe}.x86-64.nexe ${script}
     cd ${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}/${NACL_BUILD_SUBDIR}/test && make check
   else
     local nexe=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}/${NACL_BUILD_SUBDIR}/test/testil
     local script=${nexe}.sh
 
     WriteSelLdrScript ${script} ${nexe}
 
     cd ${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}/${NACL_BUILD_SUBDIR}/test && make check
   fi
 }
-
-
-PackageInstall
-exit 0