Allow re-targeting of naclports install

libraries/tinyxml/nacl-tinyxml.sh

Index: libraries/tinyxml/nacl-tinyxml.sh
diff --git a/libraries/tinyxml/nacl-tinyxml.sh b/libraries/tinyxml/nacl-tinyxml.sh
index f796b9624873b8776a9e3299c4e86f9b1885f524..21abe132e66875634febb4ca13079baa3b940834 100755
--- a/libraries/tinyxml/nacl-tinyxml.sh
+++ b/libraries/tinyxml/nacl-tinyxml.sh
@@ -34,13 +34,13 @@ CustomBuildStep() {
 
 CustomInstallStep() {
   # copy libs and headers manually
-  Banner "Installing ${PACKAGE_NAME} to ${NACL_SDK_USR}"
-  ChangeDir ${NACL_SDK_USR_INCLUDE}
+  Banner "Installing ${PACKAGE_NAME} to ${NACLPORTS_PREFIX}"
+  ChangeDir ${NACLPORTS_INCLUDE}
   Remove ${PACKAGE_NAME}
   MakeDir ${PACKAGE_NAME}
   readonly THIS_PACKAGE_PATH=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_NAME}
   cp ${THIS_PACKAGE_PATH}/*.h ${PACKAGE_NAME}/
-  ChangeDir ${NACL_SDK_USR_LIB}
+  ChangeDir ${NACLPORTS_LIBDIR}
   cp ${THIS_PACKAGE_PATH}/*.a .
   DefaultTouchStep
 }