src/Pure/System/platform.scala

   private val X86 = new Regex("i.86|x86")
   private val X86_64 = new Regex("amd64|x86_64")
   private val Sparc = new Regex("sparc")
   private val PPC = new Regex("PowerPC|ppc")
 
-  def jvm_platform(): String =
+  lazy val jvm_platform: String =
   {
     val arch =
       java.lang.System.getProperty("os.arch") match {
         case X86() => "x86"
         case X86_64() => "x86_64"