Fix built-in examples update during build

Previously, the built-in examples assembly step of the build system set the
`final_folder` parameter of the `unzip` target to the true final
installation location of the examples.

The behavior of the `unzip` target is to only unzip the archive if
`final_folder` doesn't exist. Because that folder will exist any time a
previous build has been done and `ant clean` was not run, the archive will
not be unzipped. This causes the build to fail after an update to the
built-in examples version when it attempts to copy the examples from the
version-dependent extraction staging folder to the final location.

The fix is to set the `final_folder` parameter to the version-dependent
staging folder location, which will cause the extraction to happen every
time the examples version is updated, but to be skipped when there was no
update.

Author: per1234

build/build.xml

@@ -242,7 +242,8 @@
     <antcall target="unzip">
       <param name="archive_file" value="${BUILT-IN-EXAMPLES-REPOSITORY-NAME}-${BUILT-IN-EXAMPLES-VERSION}.zip" />
       <param name="archive_url" value="https://github.com/${BUILT-IN-EXAMPLES-REPOSITORY-OWNER}/${BUILT-IN-EXAMPLES-REPOSITORY-NAME}/archive/${BUILT-IN-EXAMPLES-VERSION}.zip" />
-      <param name="final_folder" value="${BUILT-IN-EXAMPLES-FINAL-PATH}" />
+      <!-- Because the presence of this folder determines whether the extraction happens, this must point to a version-dependent path, otherwise updates will fail -->
+      <param name="final_folder" value="${BUILT-IN-EXAMPLES-STAGING-PATH}/${BUILT-IN-EXAMPLES-REPOSITORY-NAME}-${BUILT-IN-EXAMPLES-VERSION}/examples" />
       <param name="dest_folder" value="${BUILT-IN-EXAMPLES-STAGING-PATH}" />
     </antcall>