helper/seccomp: separate seccomp package

Signed-off-by: Ophestra <cat@gensokyo.uk>

helper/seccomp/export.go

@@ -0,0 +1,17 @@
+package seccomp
+
+import (
+	"io"
+	"os"
+)
+
+func Export(opts SyscallOpts) (f *os.File, err error) {
+	if f, err = tmpfile(); err != nil {
+		return
+	}
+	if err = exportFilter(f.Fd(), opts); err != nil {
+		return
+	}
+	_, err = f.Seek(0, io.SeekStart)
+	return
+}