How can I override global OPTIONS_UNSET for specific port in make.conf? www/xcache

[Miroslav Lachman]

I don't need DOCS, EXAMPLES etc. for each port as I normaly do not use 
them on servers.
I have this line in make.conf

OPTIONS_UNSET= X11 GUI CUPS DOCS EXAMPLES NLS

Now I need www/xcache port installed with EXAMPLES.
I tried following in make.conf:

xcache_SET= EXAMPLES

or

xcache_SET_FORCE= EXAMPLES

In both cases, xcache is installed without EXAMPLES.

So how can I have globally disabled EXAMPLES and enable it only for one 
specific port?

Miroslav Lachman