fix behavior of System.exit trapping

Installing one globally for the JVM live-time and make behavior dependent
on a thread local variable seems safer than globally switching it out
and having race conditions.

Also now all other calls are forwarded to a potential Nailgun
SecurityManager, which should fix some bugs.

1 files changed, 4 insertions, 2 deletions

diff --git a/stage1/Stage1Lib.scala b/stage1/Stage1Lib.scala
index 9e500a3..43c4f84 100644
--- a/stage1/Stage1Lib.scala
+++ b/stage1/Stage1Lib.scala
@@ -251,14 +251,16 @@ ${files.sorted.mkString(" \\\n")}
   }
 
   def trapExitCode( code: => ExitCode ): ExitCode = {
+    val trapExitCodeBefore = NailgunLauncher.trapExitCode.get
     try{
-      System.setSecurityManager( new TrapSecurityManager )
+      NailgunLauncher.trapExitCode.set(true)
       code
     } catch {
       case CatchTrappedExitCode(exitCode) =>
+        logger.stage1(s"caught exit code $exitCode")
         exitCode
     } finally {
-      System.setSecurityManager(NailgunLauncher.defaultSecurityManager)
+      NailgunLauncher.trapExitCode.set(trapExitCodeBefore)
     }
   }