dev-util/cmocka seems an unusual unconditional dependency. It looks like it's only used for testing (naturally) but the build system checks for it even if we're not going to run tests.
I suggest we allow "using" the bundled version when USE=-test (which won't ever actually be used for anything) to avoid the system dependency.
*** Bug 814578 has been marked as a duplicate of this bug. ***
Same for net-fs/samba.