Use a virtual provider instead of a hard dependency so that if gtk+-native is
required in some configuration, this provider can be changed and then
gtk+-native and gtk-update-icon-cache-native won't be both built and conflict in
the sysroot.
(From OE-Core rev: 73c5458c7f041157832123696814b02df2b55090)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>