Make GetDataMember use an out param

Author: aaronj0

clingwrapper/src/clingwrapper.cxx

@@ -1627,9 +1627,10 @@ bool Cppyy::IsStaticMethod(TCppMethod_t method)
 //     return (TCppIndex_t)0;         // unknown class?
 // }
 
-std::vector<Cppyy::TCppScope_t> Cppyy::GetDatamembers(TCppScope_t scope)
+void Cppyy::GetDatamembers(TCppScope_t scope, std::vector<TCppScope_t>& datamembers)
 {
-    return Cpp::GetDatamembers(scope);
+    Cpp::GetDatamembers(scope, datamembers);
+    Cpp::GetStaticDatamembers(scope, datamembers);
 }
 
 bool Cppyy::CheckDatamember(TCppScope_t scope, const std::string& name) {

clingwrapper/src/cpp_cppyy.h

@@ -334,7 +334,7 @@ namespace Cppyy {
     // RPY_EXPORTED
     // TCppIndex_t GetNumDatamembers(TCppScope_t scope, bool accept_namespace = false) { return 0; }
     RPY_EXPORTED
-    std::vector<TCppScope_t> GetDatamembers(TCppScope_t scope);
+    void GetDatamembers(TCppScope_t scope, std::vector<TCppScope_t>& datamembers);
     // GetDatamemberName is unused.
     // RPY_EXPORTED
     // std::string GetDatamemberName(TCppScope_t scope, TCppIndex_t idata) { return ""; }