Merge pull request #396 in G/fastr from...

Merge pull request #396 in G/fastr from ~STEPAN.SINDELAR_ORACLE.COM/fastr:fix/fortran-truffle-boundary to master

* commit 'a97d87a6':
  Add @TruffleBoundary over Fortran.lookup method

com.oracle.truffle.r.nodes.builtin/src/com/oracle/truffle/r/nodes/builtin/base/foreign/ForeignFunctions.java

@@ -228,6 +228,7 @@ public class ForeignFunctions {
         }
 
         @Override
+        @TruffleBoundary
         protected RExternalBuiltinNode lookupBuiltin(RList f) {
             switch (lookupName(f)) {
                 case "dqrdc2":