src/Pure/System/platform.scala

--- a/src/Pure/System/platform.scala	Wed Jun 30 16:53:33 2021 +0200
+++ b/src/Pure/System/platform.scala	Wed Jun 30 20:57:38 2021 +0200
@@ -11,7 +11,7 @@
 {
   /* platform family */
 
-  def is_windows: Boolean = isabelle.setup.Isabelle_Env.is_windows
+  val is_windows: Boolean = isabelle.setup.Environment.is_windows()
   val is_linux: Boolean = System.getProperty("os.name", "") == "Linux"
   val is_macos: Boolean = System.getProperty("os.name", "") == "Mac OS X"
   val is_unix: Boolean = is_linux || is_macos