Add build flag for webpush

server/server_webpush.go

@@ -15,6 +15,10 @@ import (
 )
 
 const (
+	// WebPushAvailable is a constant used to indicate that WebPush support is available.
+	// It can be disabled with the 'nowebpush' build tag.
+	WebPushAvailable = true
+
 	webPushTopicSubscribeLimit = 50
 )
 

server/server_webpush_dummy.go

@@ -6,6 +6,12 @@ import (
 	"net/http"
 )
 
+const (
+	// WebPushAvailable is a constant used to indicate that WebPush support is available.
+	// It can be disabled with the 'nowebpush' build tag.
+	WebPushAvailable = false
+)
+
 func (s *Server) handleWebPushUpdate(w http.ResponseWriter, r *http.Request, v *visitor) error {
 	return errHTTPNotFound
 }

server/server_webpush_test.go

@@ -1,3 +1,5 @@
+//go:build !nowebpush
+
 package server
 
 import (