@PURPOSE@
This tries to clean up the cache directory of <parameter>cache_dir</parameter>.
This returns FcTrue if the operation is successfully complete. otherwise FcFalse.
+@SINCE@ 2.9.91
@@
@RET@ void
@DESC@
This tries to create CACHEDIR.TAG file at the cache directory registered
to <parameter>config</parameter>.
+@SINCE@ 2.9.91
@@