buildroot

package/cmake: propagate libuv dependencies

In c2c06a6de02,  cmake version was bumped and a new dependency on libuv
was added, but it did not propagate all the dependencies of libuv,
missing sync_4 (probably because sync_4 was added after the patch was
sent on the list, but before it was applied to the tree).

Fix that, which fixes unmet dependencies.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>