Cleanup build constraints

Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>

cmd/containerd-shim-runc-v1/main.go

@@ -1,5 +1,4 @@
 //go:build linux
-// +build linux
 
 /*
    Copyright The containerd Authors.

cmd/containerd-shim-runc-v2/main.go

@@ -1,5 +1,4 @@
 //go:build linux
-// +build linux
 
 /*
    Copyright The containerd Authors.

cmd/containerd-shim/main_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/containerd-stress/rlimit_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows && !freebsd
-// +build !windows,!freebsd
 
 /*
    Copyright The containerd Authors.

cmd/containerd/builtins/aufs_linux.go

@@ -1,5 +1,4 @@
 //go:build !no_aufs
-// +build !no_aufs
 
 /*
    Copyright The containerd Authors.

cmd/containerd/builtins/btrfs_linux.go

@@ -1,5 +1,4 @@
 //go:build !no_btrfs && cgo
-// +build !no_btrfs,cgo
 
 /*
    Copyright The containerd Authors.

cmd/containerd/builtins/builtins_unix.go

@@ -1,5 +1,4 @@
 //go:build darwin || freebsd || solaris
-// +build darwin freebsd solaris
 
 /*
    Copyright The containerd Authors.

cmd/containerd/builtins/devmapper_linux.go

@@ -1,5 +1,4 @@
 //go:build !no_devmapper
-// +build !no_devmapper
 
 /*
    Copyright The containerd Authors.

cmd/containerd/builtins/tracing.go

@@ -1,5 +1,4 @@
 //go:build !no_tracing
-// +build !no_tracing
 
 /*
    Copyright The containerd Authors.

cmd/containerd/builtins/zfs_linux.go

@@ -1,5 +1,4 @@
 //go:build !no_zfs
-// +build !no_zfs
 
 /*
    Copyright The containerd Authors.

cmd/containerd/command/main_unix.go

@@ -1,5 +1,4 @@
 //go:build linux || darwin || freebsd || solaris
-// +build linux darwin freebsd solaris
 
 /*
    Copyright The containerd Authors.

cmd/containerd/command/notify_unsupported.go

@@ -1,5 +1,4 @@
 //go:build !linux
-// +build !linux
 
 /*
    Copyright The containerd Authors.

cmd/containerd/command/service_unsupported.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/ctr/app/main_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/commands_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/namespaces/namespaces_other.go

@@ -1,5 +1,4 @@
 //go:build !linux
-// +build !linux
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/pprof/pprof_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/run/run_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/shim/io_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/shim/shim.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/signals_notlinux.go

@@ -1,5 +1,4 @@
 //go:build !linux
-// +build !linux
 
 /*
    Copyright The containerd Authors.

cmd/ctr/commands/tasks/tasks_unix.go

@@ -1,5 +1,4 @@
 //go:build !windows
-// +build !windows
 
 /*
    Copyright The containerd Authors.