Set SysProcAttr Foreground: true when user run cmd

Fixes: #404

local/runner.go

@@ -277,7 +277,7 @@ func (r *Runner) buildCmd() (*exec.Cmd, error) {
 	cmd.Env = os.Environ()
 	cmd.Dir = r.pidFile.Dir
 
-	if err := buildCmd(cmd); err != nil {
+	if err := buildCmd(cmd, r.mode == RunnerModeOnce); err != nil {
 		return nil, err
 	}
 

local/runner_posix.go

@@ -8,11 +8,12 @@ import (
 	"syscall"
 )
 
-func buildCmd(cmd *exec.Cmd) error {
+func buildCmd(cmd *exec.Cmd, foreground bool) error {
 	cmd.SysProcAttr = &syscall.SysProcAttr{
 		// isolate each command in a new process group that we can cleanly send
 		// signal to when we want to stop it
-		Setpgid: true,
+		Setpgid:    true,
+		Foreground: foreground,
 	}
 
 	return nil

local/runner_windows.go

@@ -2,6 +2,6 @@ package local
 
 import "os/exec"
 
-func buildCmd(*exec.Cmd) error {
+func buildCmd(*exec.Cmd, bool) error {
 	return nil
 }