Add top level build script for building packages.

ports/ruby/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
 
 MAKE_TARGETS="pprogram"
 INSTALL_TARGETS="install-nodoc DESTDIR=${NACL_TOOLCHAIN_INSTALL}"
 
 EXECUTABLES="ruby${NACL_EXEEXT} pepper-ruby${NACL_EXEEXT}"
 
 ConfigureStep() {
   # We need to build a host version of ruby for use during the nacl
   # build.
   HOST_BUILD=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}/build-nacl-host
@@ skipping 13 matching lines @@
   export CXX=${NACLCXX}
   export AR=${NACLAR}
   export RANLIB=${NACLRANLIB}
   export PKG_CONFIG_PATH=${NACLPORTS_LIBDIR}/pkgconfig
   export PKG_CONFIG_LIBDIR=${NACLPORTS_LIBDIR}
   export FREETYPE_CONFIG=${NACLPORTS_PREFIX_BIN}/freetype-config
   export CFLAGS=${NACLPORTS_CFLAGS}
   export CXXFLAGS=${NACLPORTS_CXXFLAGS}
   export LDFLAGS=${NACLPORTS_LDFLAGS}
   export PATH=${NACL_BIN_PATH}:${PATH};
-  local SRC_DIR=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}
   if [ ! -f "${SRC_DIR}/configure" ]; then
     echo "No configure script found"
     return
   fi
-  local DEFAULT_BUILD_DIR=${SRC_DIR}/${NACL_BUILD_SUBDIR}
-  local BUILD_DIR=${NACL_BUILD_DIR:-${DEFAULT_BUILD_DIR}}
   MakeDir ${BUILD_DIR}
   ChangeDir ${BUILD_DIR}
   echo "Directory: $(pwd)"
 
   # TODO(sbc): remove once getaddrinfo() is working
   EXTRA_CONFIGURE_ARGS=--disable-ipv6
 
   if [ ${NACL_GLIBC} != 1 ]; then
     EXTRA_CONFIGURE_ARGS+=" --with-static-linked-ext --with-newlib"
     export LIBS="-lglibc-compat"
@@ skipping 29 matching lines @@
 
 BuildStep() {
   DefaultBuildStep
   if [ $NACL_ARCH != "pnacl" ]; then
     WriteSelLdrScript ruby ruby.nexe
   else
     # Just write the x86-64 version out for now.
     TranslateAndWriteSelLdrScript ruby.pexe x86-64 ruby.x86-64.nexe ruby
   fi
 }
-
-PackageInstall
-exit 0