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-empty-include-and-non-empty-exclude-list b/testsuite/tar/tar-handles-empty-include-and-non-empty-exclude-list
index b76f023..5033642 100644
--- a/testsuite/tar/tar-handles-empty-include-and-non-empty-exclude-list
+++ b/testsuite/tar/tar-handles-empty-include-and-non-empty-exclude-list
@@ -1,4 +1,5 @@
-# FEATURE: CONFIG_FEATURE_TAR_EXCLUDE
+# FEATURE: CONFIG_FEATURE_TAR_FROM
+# FEATURE: CONFIG_FEATURE_TAR_CREATE
 touch foo
 tar cf foo.tar foo
 echo foo >foo.exclude