Allow re-targeting of naclports install

libraries/fftw-3.2.2/nacl-fftw-3.2.2.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.
 #
 
 # nacl-fftw-3.2.2.sh
 #
 # usage:  nacl-fftw-3.2.2.sh
 #
 # This script downloads, patches, and builds fftw-3.2.2 for Native Client.
 #
 
 source pkg_info
 source ../../build_tools/common.sh
 
 CustomConfigureStep() {
   Banner "Configuring ${PACKAGE_NAME}"
   # Export the nacl tools.
   export CC=${NACLCC}
   export CXX=${NACLCXX}
   export AR=${NACLAR}
   export RANLIB=${NACLRANLIB}
-  export PKG_CONFIG_PATH=${NACL_SDK_USR_LIB}/pkgconfig
-  export PKG_CONFIG_LIBDIR=${NACL_SDK_USR_LIB}
+  export PKG_CONFIG_PATH=${NACLPORTS_LIBDIR}/pkgconfig
+  export PKG_CONFIG_LIBDIR=${NACLPORTS_LIBDIR}
   export PATH=${NACL_BIN_PATH}:${PATH};
   ChangeDir ${NACL_PACKAGES_REPOSITORY}/${PACKAGE_NAME}
   if [ ${NACL_ARCH} = "pnacl" ] ; then
     extra=
   else
     extra="--enable-sse2"
   fi
 
-  ./configure --prefix=${NACL_SDK_USR} --host=nacl ${extra}
+  ./configure --prefix=${NACLPORTS_PREFIX} --host=nacl ${extra}
 }
 
 
 CustomPackageInstall() {
   DefaultPreInstallStep
   DefaultDownloadStep
   DefaultExtractStep
   DefaultPatchStep
   CustomConfigureStep
   DefaultBuildStep
   DefaultInstallStep
   DefaultCleanUpStep
 }
 
 
 CustomPackageInstall
 exit 0