fix undefined processExists error (megaease#87)

* fix error
daemon/daemon.go:90:5: undefined: processExists
just a copy of daemon_darwin

* remove openbsd and rename daemon_unix
also update the build contraints

* update the build contraints

* this got added by vscode

* added the rest of the systems that should work with this
file without a problem

* Exclude linux & windows instead
now we support more platforms out of the box

daemon/daemon_linux.go

@@ -1,5 +1,5 @@
-//go:build !windows && !darwin
-// +build !windows,!darwin
+//go:build linux
+// +build linux
 
 /*
  * Copyright (c) 2022, MegaEase

daemon/daemon_darwin.go → daemon/daemon_unix.go

@@ -1,5 +1,5 @@
-//go:build darwin
-// +build darwin
+//go:build !linux && !windows
+// +build !linux,!windows
 
 /*
  * Copyright (c) 2022, MegaEase
@@ -23,7 +23,7 @@ package daemon
 import "golang.org/x/sys/unix"
 
 func processExists(pid int) bool {
- // OS X does not have a proc filesystem.
+ // OS X & BSD systems don't have a proc filesystem.
  // Use kill -0 pid to judge if the process exists.
  err := unix.Kill(pid, 0)
  return err == nil

go.mod

@@ -17,6 +17,7 @@ require (
  go.mongodb.org/mongo-driver v1.9.0
  golang.org/x/crypto v0.0.0-20220411220226-7b82a4e95df4
  golang.org/x/exp v0.0.0-20220328175248-053ad81199eb
+ golang.org/x/sys v0.0.0-20220503163025-988cb79eb6c6
  gopkg.in/natefinch/lumberjack.v2 v2.0.0
  gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )
@@ -47,7 +48,6 @@ require (
  github.com/xdg-go/stringprep v1.0.2 // indirect
  github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d // indirect
  golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
- golang.org/x/sys v0.0.0-20220503163025-988cb79eb6c6 // indirect
  golang.org/x/text v0.3.7 // indirect
  golang.org/x/xerrors v0.0.0-20220411194840-2f41105eb62f // indirect
  gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect