TESTS: ipc: conditionalize memfd and seals
TESTS: ipc: conditionalize memfd and seals

This fixes the Fedora 27 builds by providing fallback code for memfd_create().

Signed-off-by: Tim Janik <6ec6ff229c4e1c5bbd5933ee92e6c5832ff023bb@gnu.org>

tim-janik/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,tim-janik/beast,tim-janik/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast