Turning off an option

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

For one package (sylpheed), when I type 'make show-options', it says:

These options are enabled by default: gpgme inet6
These options are currently enabled: gpgme inet6

I'd like to delete gpgme; the machine isn't rated for private keys.
How do I do that?  I tried both

        PKG_OPTIONS.sylpheed-=gpgme

and

        PKG_OPTIONS.sylpheed=inet6

in /et/mk.conf; neither worked.

                --Steven M. Bellovin, http://www.cs.columbia.edu/~smb