diff -r 98215fa4f8d1 -r a2eebcc8bb69 src/Pure/System/platform.scala
--- a/src/Pure/System/platform.scala	Fri Nov 11 13:57:01 2016 +0100
+++ b/src/Pure/System/platform.scala	Fri Nov 11 15:24:56 2016 +0100
@@ -14,6 +14,7 @@
 {
   /* main OS variants */
 
+  val is_linux = System.getProperty("os.name", "") == "Linux"
   val is_macos = System.getProperty("os.name", "") == "Mac OS X"
   val is_windows = System.getProperty("os.name", "").startsWith("Windows")