Attempt to fix llvm 4.2 compiler errors.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
===================================================================
--- runtime/vm/raw_object.h	(revision 38242)
+++ runtime/vm/raw_object.h	(working copy)
@@ -960,12 +960,17 @@
     int16_t try_index_;
   };
 
-  static const intptr_t kFullRecSize = sizeof(PcDescriptorRec);
-  static const intptr_t kCompressedRecSize = kFullRecSize - sizeof(int16_t);
+  static intptr_t RecordSize(bool has_try_index) {
+    return has_try_index ? RawPcDescriptors::kFullRecSize
+                         : RawPcDescriptors::kCompressedRecSize;
+  }
 
  private:
   RAW_HEAP_OBJECT_IMPLEMENTATION(PcDescriptors);
 
+  static const intptr_t kFullRecSize = sizeof(PcDescriptorRec);
+  static const intptr_t kCompressedRecSize = kFullRecSize - sizeof(int16_t);
+
   intptr_t record_size_in_bytes_;
   intptr_t length_;  // Number of descriptors.