GP-3276 Put all C++ classes in ghidra namespace

Ghidra/Features/Decompiler/src/decompile/cpp/unionresolve.cc

@@ -16,6 +16,8 @@
 #include "unionresolve.hh"
 #include "funcdata.hh"
 
+namespace ghidra {
+
 /// The original parent must either be a union, a pointer to a union, or a partial union.
 /// The object is set up initially to resolve to the parent.
 /// \param parent is the original parent data-type
@@ -1106,3 +1108,4 @@ ScoreUnionFields::ScoreUnionFields(TypeFactory &tgrp,TypeUnion *unionType,int4 o
   computeBestIndex();
 }
 
+} // End namespace ghidra