Now persistent expression data no longer lives with the Target, but rather with

the corresponding TypeSystem.  This makes sense because what kind of data there
is -- and how it can be looked up -- depends on the language.

Functionality that is common to all type systems is factored out into
PersistentExpressionState.

llvm-svn: 248934

lldb/source/Expression/ExpressionVariable.cpp

@@ -30,3 +30,7 @@ ExpressionVariable::GetValueBytes()
     }
     return NULL;
 }
+
+PersistentExpressionState::~PersistentExpressionState ()
+{
+}