Use PACKAGECONFIG to add options for ca-certificates, gnutls, and libproxy.
Enable ca-certificates by default as all it needs to know is the right path,
ca-certificates not being installed isn't fatal.
(From OE-Core rev: 1f03b6aa9e475f341815788613513ff63add8a5f)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>