run: drop Pdeathsig

it is not safe to use prctl(PR_SET_PDEATHSIG) in a Go program since
the parent of the process is considered the *thread* that created the
child process, and the Go runtime can free a thread at any time.   We
would either need to lock the thread, or simpler just not use it.

[NO NEW TESTS NEEDED]

Closes: https://github.com/containers/podman/issues/17918

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

run_freebsd.go

@@ -7,10 +7,8 @@ import (
 	"errors"
 	"fmt"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"strings"
-	"syscall"
 	"unsafe"
 
 	"github.com/containers/buildah/bind"
@@ -531,14 +529,6 @@ func addRlimits(ulimit []string, g *generate.Generator, defaultUlimits []string)
 	return nil
 }
 
-// setPdeathsig sets a parent-death signal for the process
-func setPdeathsig(cmd *exec.Cmd) {
-	if cmd.SysProcAttr == nil {
-		cmd.SysProcAttr = &syscall.SysProcAttr{}
-	}
-	cmd.SysProcAttr.Pdeathsig = syscall.SIGKILL
-}
-
 // Create pipes to use for relaying stdio.
 func runMakeStdioPipe(uid, gid int) ([][]int, error) {
 	stdioPipe := make([][]int, 3)