Add interesting fields to usage report (fixes #559)

lib/upgrade/upgrade_supported.go

@@ -29,6 +29,8 @@ import (
 	"github.com/syncthing/syncthing/lib/signature"
 )
 
+const DisabledByCompilation = false
+
 // This is an HTTP/HTTPS client that does *not* perform certificate
 // validation. We do this because some systems where Syncthing runs have
 // issues with old or missing CA roots. It doesn't actually matter that we

lib/upgrade/upgrade_unsupp.go

@@ -8,6 +8,8 @@
 
 package upgrade
 
+const DisabledByCompilation = true
+
 func upgradeTo(binary string, rel Release) error {
 	return ErrUpgradeUnsupported
 }