Allow re-targeting of naclports install

libraries/pixman-0.16.2/nacl-pixman-0.16.2.sh

Index: libraries/pixman-0.16.2/nacl-pixman-0.16.2.sh
diff --git a/libraries/pixman-0.16.2/nacl-pixman-0.16.2.sh b/libraries/pixman-0.16.2/nacl-pixman-0.16.2.sh
index 15755f94e815886f31c9c70e051b977026e8aa8d..79955bc2c98874e6ea46b6b9933768335a37ec02 100755
--- a/libraries/pixman-0.16.2/nacl-pixman-0.16.2.sh
+++ b/libraries/pixman-0.16.2/nacl-pixman-0.16.2.sh
@@ -21,8 +21,8 @@ CustomConfigureStep() {
   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}
   Remove ${PACKAGE_NAME}-build
@@ -32,10 +32,10 @@ CustomConfigureStep() {
   ../configure \
     --host=nacl \
     --disable-shared \
-    --prefix=${NACL_SDK_USR} \
-    --exec-prefix=${NACL_SDK_USR} \
-    --libdir=${NACL_SDK_USR_LIB} \
-    --oldincludedir=${NACL_SDK_USR_INCLUDE} \
+    --prefix=${NACLPORTS_PREFIX} \
+    --exec-prefix=${NACLPORTS_PREFIX} \
+    --libdir=${NACLPORTS_LIBDIR} \
+    --oldincludedir=${NACLPORTS_INCLUDE} \
     --with-http=off \
     --with-html=off \
     --with-ftp=off \