use file name suffix for OS-specific code wherever possible (#5787)

internal/externalcmd/cmd_os_windows.go

@@ -1,5 +1,3 @@
-//go:build windows
-
 package externalcmd
 
 import (

internal/externalcmd/cmd_test.go

@@ -1,5 +1,3 @@
-//go:build !windows
-
 package externalcmd
 
 import (

internal/logger/destination_syslog_darwin.go

@@ -1,5 +1,3 @@
-//go:build darwin || windows
-
 package logger
 
 import "fmt"

internal/logger/destination_syslog_windows.go

@@ -0,0 +1,7 @@
+package logger
+
+import "fmt"
+
+func newDestinationSyslog(_ string) (destination, error) {
+	return nil, fmt.Errorf("syslog is not available on macOS and Windows")
+}

internal/rlimit/rlimit_windows.go

@@ -1,5 +1,3 @@
-//go:build windows
-
 package rlimit
 
 func Raise() error {

internal/staticsources/rpicamera/camera_linux_arm.go

@@ -1,5 +1,3 @@
-//go:build linux && arm
-
 package rpicamera
 
 import (

internal/staticsources/rpicamera/camera_linux_arm64.go

@@ -1,5 +1,3 @@
-//go:build linux && arm64
-
 package rpicamera
 
 import (