Value set: add declared-on-type entry member

This is essentially specific to the security scanner's needs, but is
also impossible to add to value-set without templating the class, thus
moving ~2000LOC into its header file. This is the temporary kludge until
we bite the bullet and do that, or think of something smarter.

Author: smowton

src/pointer-analysis/value_set.h

@@ -102,7 +102,7 @@ class value_sett
     object_mapt object_map;
     idt identifier;
     std::string suffix;
-
+    typet declared_on_type;
     entryt()
     {
     }
@@ -112,6 +112,13 @@ class value_sett
       suffix(_suffix)
     {
     }
+
+    entryt(const idt &_identifier, const std::string &_suffix, const typet &_declared_on_type):
+      identifier(_identifier),
+      suffix(_suffix),
+      declared_on_type(_declared_on_type)
+    {
+    }
   };
 
   typedef std::set<exprt> expr_sett;