The attached patch allows Guix's test suite to pass (and thus, the
"guix" package to be built) on systems that lack support for swap
devices; that is, systems that not only do not have a swap device
enabled but do not have even support for memory paging built into the
kernel (e.g. Linux built without CONFIG_SWAP). This might be the case
for a small home server, for example, on which the workload is
predictable but memory is otherwise at a premium.
On these systems the "swapon" and "swapoff" syscalls return ENOSYS
("Function not implemented"). The patch modifies the relevant tests in
tests/syscalls.scm to accept this as a valid return value.