Setns = fun(CONFIG) -> case os:type() of
        {unix,linux} ->
            Prog = "
#define _GNU_SOURCE
#include <sched.h>
int main(int argc, char *argv[]) {
    (void)setns(0,0);
    return 0;
}",
            file:write_file("test/test_setns.c", Prog),
            Retval = os:cmd("gcc -o /dev/null test/test_setns.c > /dev/null 2>&1; printf \"%d\" $?"),
            file:delete("test/test_setns.c"),
            case Retval of
                "0" ->
                    lists:map(fun
                            ({port_env, Env}) ->
                                Cflags = proplists:get_value("EXE_CFLAGS", Env, "")
                                    ++ " -DHAVE_SETNS",
                                {port_env, lists:keyreplace("EXE_CFLAGS", 1, Env,
                                    {"EXE_CFLAGS", Cflags})};
                            (N) ->
                                N
                            end, CONFIG);
                _ ->
                    CONFIG
            end;
        _ ->
            CONFIG
    end
end,
Seccomp = fun(CONFIG) -> case os:type() of
        {unix,linux} ->
            Prog = "
#include <linux/seccomp.h>
int main(int argc, char *argv[]) {
#ifdef SECCOMP_MODE_FILTER
    return 0;
#else
    return 1;
#endif
}",
            file:write_file("test/test_seccomp.c", Prog),
            Retval = os:cmd("gcc -o /dev/null test/test_seccomp.c > /dev/null 2>&1; printf \"%d\" $?"),
            file:delete("test/test_seccomp.c"),
            case Retval of
                "0" ->
                    lists:map(fun
                            ({port_env, Env}) ->
                                Cflags = proplists:get_value("EXE_CFLAGS", Env, "")
                                    ++ " -DHAVE_SECCOMP",
                                {port_env, lists:keyreplace("EXE_CFLAGS", 1, Env,
                                    {"EXE_CFLAGS", Cflags})};
                            (N) ->
                                N
                            end, CONFIG);
                _ ->
                    CONFIG
            end;
        _ ->
            CONFIG
    end
end,
lists:foldl(fun(Fun, Cfg) ->
        Fun(Cfg)
    end,
    CONFIG,
    [Setns, Seccomp]
).