Isolate code better for unused options, config option to enable long
options, add some conditions to the tar tests in testsuite.
diff --git a/testsuite/tar/tar-handles-cz-options b/testsuite/tar/tar-handles-cz-options
index 1049c6d..5b55e46 100644
--- a/testsuite/tar/tar-handles-cz-options
+++ b/testsuite/tar/tar-handles-cz-options
@@ -1,3 +1,5 @@
+# FEATURE: CONFIG_FEATURE_TAR_CREATE
+# FEATURE: CONFIG_FEATURE_TAR_GZIP
 touch foo
 busybox tar czf foo.tar.gz foo
 gzip -d foo.tar.gz