Allow re-targeting of naclports install

libraries/libtomcrypt-1.17/nacl-libtomcrypt-1.17.sh

Index: libraries/libtomcrypt-1.17/nacl-libtomcrypt-1.17.sh
diff --git a/libraries/libtomcrypt-1.17/nacl-libtomcrypt-1.17.sh b/libraries/libtomcrypt-1.17/nacl-libtomcrypt-1.17.sh
index 4f1623f69a910a4ee9972635a481cf59fd9bdf52..1d01dfd7385d358952c6a2f4629dd0fa767d9024 100755
--- a/libraries/libtomcrypt-1.17/nacl-libtomcrypt-1.17.sh
+++ b/libraries/libtomcrypt-1.17/nacl-libtomcrypt-1.17.sh
@@ -32,12 +32,12 @@ 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 ${PACKAGE_NAME}
   readonly THIS_PACKAGE_PATH=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_NAME}
   cp ${THIS_PACKAGE_PATH}/src/headers/*.h ./
-  ChangeDir ${NACL_SDK_USR_LIB}
+  ChangeDir ${NACLPORTS_LIBDIR}
   cp ${THIS_PACKAGE_PATH}/*.a .
   DefaultTouchStep
 }