Allow re-targeting of naclports install

libraries/Mesa-7.6/nacl-Mesa-7.6.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-Mesa-7.6.sh
 #
 # usage:  nacl-Mesa-7.6.sh
 #
 # this script downloads, patches, and builds Mesa for Native Client
 #
 
 source pkg_info
 source ../../build_tools/common.sh
 
 CustomConfigureStep() {
   # export the nacl tools
   export CC=${NACLCC}
   export CXX=${NACLCXX}
   export AR=${NACLAR}
   export LD=${NACLLD}
   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_PREFIX}/lib/pkgconfig
+  export PKG_CONFIG_LIBDIR=${NACLPORTS_PREFIX}/lib
   export PATH=${NACL_BIN_PATH}:${PATH};
   export X11_INCLUDES=
   cd ${NACL_PACKAGES_REPOSITORY}/${PACKAGE_NAME}
   ./configure \
     --host=nacl \
     --disable-shared \
     --enable-static \
-    --prefix=${NACL_SDK_USR} \
-    --exec-prefix=${NACL_SDK_USR} \
-    --libdir=${NACL_SDK_USR}/lib \
-    --oldincludedir=${NACL_SDK_USR}/include \
-    --datarootdir=${NACL_SDK_USR} \
+    --prefix=${NACLPORTS_PREFIX} \
+    --exec-prefix=${NACLPORTS_PREFIX} \
+    --libdir=${NACLPORTS_PREFIX}/lib \
+    --oldincludedir=${NACLPORTS_PREFIX}/include \
+    --datarootdir=${NACLPORTS_PREFIX} \
     --disable-gl-osmesa \
     --with-x=no \
     --with-driver=osmesa \
     --disable-asm \
     --disable-glut \
     --disable-gallium \
     --disable-egl \
     --disable-glw
 }
 
@@ skipping 12 matching lines @@
   DefaultPatchStep
   CustomConfigureStep
   DefaultBuildStep
   CustomInstallStep
   DefaultCleanUpStep
 }
 
 
 CustomPackageInstall
 exit 0