C++: Add upgrade and downgrade scripts

Author: jketema

cpp/downgrades/e38346051783182ea75822e4adf8d4c6a949bc37/builtintypes.ql

@@ -0,0 +1,9 @@
+class BuiltinType extends @builtintype {
+  string toString() { none() }
+}
+
+from BuiltinType id, string name, int kind, int new_kind, int size, int sign, int alignment
+where
+  builtintypes(id, name, kind, size, sign, alignment) and
+  if kind = 63 then new_kind = 1 else new_kind = kind
+select id, name, new_kind, size, sign, alignment

cpp/downgrades/e38346051783182ea75822e4adf8d4c6a949bc37/derivedtypes.ql

@@ -0,0 +1,9 @@
+class Type extends @type {
+  string toString() { none() }
+}
+
+from Type type, string name, int kind, int new_kind, Type type_id
+where
+  derivedtypes(type, name, kind, type_id) and
+  if kind = 63 then new_kind = 5 else /* @gnu_vector */ new_kind = kind
+select type, name, new_kind, type_id