This begins a pledge() implementation. This also
retires the previous syscall grouping approach,
as pledge() is the superior mechanism.
Squashed:
test: Begin basic pledge test
pledge: Begin EXILE_SYSCALL_PLEDGE_UNIX/EXILE_SYSCALL_PLEDGE_INET
test: Add pledge socket test
Introduce EXILE_SYSCALL_PLEDGE_DENY_ERROR, remove exile_policy->pledge_policy
pledge: Add PROT_EXEC
Squashed:
test: Adjust existing to new API with arg filters
test: Add tests for low-level seccomp args filter API
test: Add seccomp_filter_mixed()
test: Switch to syscall() everywhere
append_syscall_to_bpf(): Apply EXILE_SYSCALL_EXIT_BPF_NO_MATCH also for sock_filter.jt
qssb.h was a preliminary name and can't be pronounced smoothly.
exile.h is more fitting and it's also short. Something exiled is essentially
something isolated, which is pretty much what this library does (isolation from
resources such as file system, network and others accessible by system calls).
