Log Message:
Update clamav so that milter support is optional.

However currently milter support is disabled, as it requires strerror_r to
be available, which it isn't on -current.

Note this required the fixing of the milter tests in the configure.in file.
It seemed if you used --disable-milter and the .h file was in the include
path, eg on -current it's in /usr/include/libmilter it was found and used.

We now have a want_milter for the --enable/disable-milter, which will
trigger the tests to setup have_milter.

Once I've sorted out the strerror_r problem in -current I'll enable the
milter support (or if someone tells me it works with pth)

Bump PKGREVISION.