exec: always hide cmd window on Windows

exec/exec.go

@@ -84,6 +84,7 @@ func (r *Runner) Run(name string, stdout io.Writer, stdin io.Reader, args ...str
 	} else {
 		cmd = exec.Command(entry.Path, fullArgs...)
 	}
+	applyOSSpecificCmdOpts(cmd)
 
 	var stderr bytes.Buffer
 	if stdin != nil {

exec/exec_all.go

@@ -0,0 +1,7 @@
+//go:build !windows
+
+package exec
+
+import "os/exec"
+
+func applyOSSpecificCmdOpts(cmd *exec.Cmd) {}

exec/exec_windows.go

@@ -0,0 +1,12 @@
+//go:build windows
+
+package exec
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func applyOSSpecificCmdOpts(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
+}