feature/buildfeatures: split const bools out of the featuretags package, add Has prefix

This renames the package+symbols in the earlier 17ffa80138 to be
in their own package ("buildfeatures") and start with the word "Has"
like "if buildfeatures.HasFoo {".

Updates #12614

Change-Id: I510e5f65993e5b76a0e163e3aa4543755213cbf6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

feature/buildfeatures/buildfeatures.go

@@ -0,0 +1,10 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:generate go run gen.go
+
+// The buildfeatures package contains boolean constants indicating which
+// features were included in the binary (via build tags), for use in dead code
+// elimination when using separate build tag protected files is impractical
+// or undesirable.
+package buildfeatures

feature/buildfeatures/feature_aws_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_aws
+
+package buildfeatures
+
+// HasAWS is whether the binary was built with support for modular feature "AWS integration".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_aws" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasAWS = false

feature/buildfeatures/feature_aws_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_aws
+
+package buildfeatures
+
+// HasAWS is whether the binary was built with support for modular feature "AWS integration".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_aws" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasAWS = true

feature/buildfeatures/feature_bird_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_bird
+
+package buildfeatures
+
+// HasBird is whether the binary was built with support for modular feature "Bird BGP integration".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_bird" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasBird = false

feature/buildfeatures/feature_bird_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_bird
+
+package buildfeatures
+
+// HasBird is whether the binary was built with support for modular feature "Bird BGP integration".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_bird" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasBird = true

feature/buildfeatures/feature_capture_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_capture
+
+package buildfeatures
+
+// HasCapture is whether the binary was built with support for modular feature "Packet capture".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_capture" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasCapture = false

feature/buildfeatures/feature_capture_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_capture
+
+package buildfeatures
+
+// HasCapture is whether the binary was built with support for modular feature "Packet capture".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_capture" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasCapture = true

feature/buildfeatures/feature_completion_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_completion
+
+package buildfeatures
+
+// HasCompletion is whether the binary was built with support for modular feature "CLI shell completion".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_completion" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasCompletion = false

feature/buildfeatures/feature_completion_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_completion
+
+package buildfeatures
+
+// HasCompletion is whether the binary was built with support for modular feature "CLI shell completion".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_completion" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasCompletion = true

feature/buildfeatures/feature_debugeventbus_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_debugeventbus
+
+package buildfeatures
+
+// HasDebugEventBus is whether the binary was built with support for modular feature "eventbus debug support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_debugeventbus" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasDebugEventBus = false

feature/buildfeatures/feature_debugeventbus_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_debugeventbus
+
+package buildfeatures
+
+// HasDebugEventBus is whether the binary was built with support for modular feature "eventbus debug support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_debugeventbus" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasDebugEventBus = true

feature/buildfeatures/feature_desktop_sessions_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_desktop_sessions
+
+package buildfeatures
+
+// HasDesktopSessions is whether the binary was built with support for modular feature "Desktop sessions support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_desktop_sessions" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasDesktopSessions = false

feature/buildfeatures/feature_desktop_sessions_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_desktop_sessions
+
+package buildfeatures
+
+// HasDesktopSessions is whether the binary was built with support for modular feature "Desktop sessions support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_desktop_sessions" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasDesktopSessions = true

feature/buildfeatures/feature_drive_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_drive
+
+package buildfeatures
+
+// HasDrive is whether the binary was built with support for modular feature "Tailscale Drive (file server) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_drive" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasDrive = false

feature/buildfeatures/feature_drive_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_drive
+
+package buildfeatures
+
+// HasDrive is whether the binary was built with support for modular feature "Tailscale Drive (file server) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_drive" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasDrive = true

feature/buildfeatures/feature_kube_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_kube
+
+package buildfeatures
+
+// HasKube is whether the binary was built with support for modular feature "Kubernetes integration".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_kube" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasKube = false

feature/buildfeatures/feature_kube_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_kube
+
+package buildfeatures
+
+// HasKube is whether the binary was built with support for modular feature "Kubernetes integration".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_kube" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasKube = true

feature/buildfeatures/feature_relayserver_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_relayserver
+
+package buildfeatures
+
+// HasRelayServer is whether the binary was built with support for modular feature "Relay server".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_relayserver" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasRelayServer = false

feature/buildfeatures/feature_relayserver_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_relayserver
+
+package buildfeatures
+
+// HasRelayServer is whether the binary was built with support for modular feature "Relay server".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_relayserver" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasRelayServer = true

feature/buildfeatures/feature_serve_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_serve
+
+package buildfeatures
+
+// HasServe is whether the binary was built with support for modular feature "Serve and Funnel support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_serve" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasServe = false

feature/buildfeatures/feature_serve_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_serve
+
+package buildfeatures
+
+// HasServe is whether the binary was built with support for modular feature "Serve and Funnel support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_serve" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasServe = true

feature/buildfeatures/feature_ssh_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_ssh
+
+package buildfeatures
+
+// HasSSH is whether the binary was built with support for modular feature "Tailscale SSH support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_ssh" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasSSH = false

feature/buildfeatures/feature_ssh_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_ssh
+
+package buildfeatures
+
+// HasSSH is whether the binary was built with support for modular feature "Tailscale SSH support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_ssh" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasSSH = true

feature/buildfeatures/feature_syspolicy_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_syspolicy
+
+package buildfeatures
+
+// HasSystemPolicy is whether the binary was built with support for modular feature "System policy configuration (MDM) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_syspolicy" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasSystemPolicy = false

feature/buildfeatures/feature_syspolicy_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_syspolicy
+
+package buildfeatures
+
+// HasSystemPolicy is whether the binary was built with support for modular feature "System policy configuration (MDM) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_syspolicy" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasSystemPolicy = true

feature/buildfeatures/feature_systray_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_systray
+
+package buildfeatures
+
+// HasSysTray is whether the binary was built with support for modular feature "Linux system tray".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_systray" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasSysTray = false

feature/buildfeatures/feature_systray_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_systray
+
+package buildfeatures
+
+// HasSysTray is whether the binary was built with support for modular feature "Linux system tray".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_systray" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasSysTray = true

feature/buildfeatures/feature_taildrop_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_taildrop
+
+package buildfeatures
+
+// HasTaildrop is whether the binary was built with support for modular feature "Taildrop (file sending) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_taildrop" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTaildrop = false

feature/buildfeatures/feature_taildrop_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_taildrop
+
+package buildfeatures
+
+// HasTaildrop is whether the binary was built with support for modular feature "Taildrop (file sending) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_taildrop" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTaildrop = true

feature/buildfeatures/feature_tailnetlock_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_tailnetlock
+
+package buildfeatures
+
+// HasTailnetLock is whether the binary was built with support for modular feature "Tailnet Lock support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_tailnetlock" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTailnetLock = false

feature/buildfeatures/feature_tailnetlock_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_tailnetlock
+
+package buildfeatures
+
+// HasTailnetLock is whether the binary was built with support for modular feature "Tailnet Lock support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_tailnetlock" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTailnetLock = true

feature/buildfeatures/feature_tap_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_tap
+
+package buildfeatures
+
+// HasTap is whether the binary was built with support for modular feature "Experimental Layer 2 (ethernet) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_tap" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTap = false

feature/buildfeatures/feature_tap_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_tap
+
+package buildfeatures
+
+// HasTap is whether the binary was built with support for modular feature "Experimental Layer 2 (ethernet) support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_tap" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTap = true

feature/buildfeatures/feature_tpm_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_tpm
+
+package buildfeatures
+
+// HasTPM is whether the binary was built with support for modular feature "TPM support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_tpm" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTPM = false

feature/buildfeatures/feature_tpm_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_tpm
+
+package buildfeatures
+
+// HasTPM is whether the binary was built with support for modular feature "TPM support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_tpm" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasTPM = true

feature/buildfeatures/feature_wakeonlan_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_wakeonlan
+
+package buildfeatures
+
+// HasWakeOnLAN is whether the binary was built with support for modular feature "Wake-on-LAN support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_wakeonlan" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasWakeOnLAN = false

feature/buildfeatures/feature_wakeonlan_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_wakeonlan
+
+package buildfeatures
+
+// HasWakeOnLAN is whether the binary was built with support for modular feature "Wake-on-LAN support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_wakeonlan" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasWakeOnLAN = true

feature/buildfeatures/feature_webclient_disabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build ts_omit_webclient
+
+package buildfeatures
+
+// HasWebClient is whether the binary was built with support for modular feature "Web client support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_webclient" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasWebClient = false

feature/buildfeatures/feature_webclient_enabled.go

@@ -0,0 +1,13 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by gen.go; DO NOT EDIT.
+
+//go:build !ts_omit_webclient
+
+package buildfeatures
+
+// HasWebClient is whether the binary was built with support for modular feature "Web client support".
+// Specifically, it's whether the binary was NOT built with the "ts_omit_webclient" build tag.
+// It's a const so it can be used for dead code elimination.
+const HasWebClient = true

feature/buildfeatures/gen.go

@@ -0,0 +1,49 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build ignore
+
+// The gens.go program generates the feature_<feature>_enabled.go
+// and feature_<feature>_disabled.go files for each feature tag.
+package main
+
+import (
+	"cmp"
+	"fmt"
+	"os"
+	"strings"
+
+	"tailscale.com/feature/featuretags"
+	"tailscale.com/util/must"
+)
+
+const header = `// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code g|e|n|e|r|a|t|e|d by gen.go; D|O N|OT E|D|I|T.
+
+`
+
+func main() {
+	header := strings.ReplaceAll(header, "|", "") // to avoid this file being marked as generated
+	for k, m := range featuretags.Features {
+		if !k.IsOmittable() {
+			continue
+		}
+		sym := "Has" + cmp.Or(m.Sym, strings.ToUpper(string(k)[:1])+string(k)[1:])
+		for _, suf := range []string{"enabled", "disabled"} {
+			bang := ""
+			if suf == "enabled" {
+				bang = "!" // !ts_omit_...
+			}
+			must.Do(os.WriteFile("feature_"+string(k)+"_"+suf+".go",
+				fmt.Appendf(nil, "%s//go:build %s%s\n\npackage buildfeatures\n\n"+
+					"// %s is whether the binary was built with support for modular feature %q.\n"+
+					"// Specifically, it's whether the binary was NOT built with the %q build tag.\n"+
+					"// It's a const so it can be used for dead code elimination.\n"+
+					"const %s = %t\n",
+					header, bang, k.OmitTag(), sym, m.Desc, k.OmitTag(), sym, suf == "enabled"), 0644))
+
+		}
+	}
+}