Python bindings work only with dd4hep sources present

[vvolkl]

Running

python -c "import dd4hep"

fails with a lengthy error message if the sources used to build dd4hep are no longer in place (so affecting most packaged versions of dd4hep) Can be reproduced by temporarily moving the dd4hep source folder.

This affects v1-10 on centos7 using LCG release 96b for example (source /cvmfs/sft.cern.ch/lcg/views/LCG_96b/x86_64-centos7-gcc62-opt/setup.sh on lxplus )

I first thought this was an issue with the lcg release, after some discussion (https://sft.its.cern.ch/jira/browse/SPI-1461) we determined that it can be reproduced locally.

[petricm]

I confirm it's still present in the head

2019-09-24 17:35 mpetric@pclcdgpu:newlocation_dd4hep$ python -c "import dd4hep"
G__DD4hep dictionary payload:17750:10: fatal error: '../src/DetectorImp.h' file not found
#include "../src/DetectorImp.h"
         ^~~~~~~~~~~~~~~~~~~~~~
Error in <TInterpreter::AutoParse>: Error parsing payload code for class dd4hep::tools::Evaluator with content:

#line 1 "G__DD4hep dictionary payload"

#ifndef BOOST_SPIRIT_USE_PHOENIX_V3
  #define BOOST_SPIRIT_USE_PHOENIX_V3 1
#endif
#ifndef BOOST_SPIRIT_USE_PHOENIX_V3
  #define BOOST_SPIRIT_USE_PHOENIX_V3 1
#endif
#ifndef DD4HEP_USE_TINYXML
  #define DD4HEP_USE_TINYXML 1
#endif
#ifndef DD4HEP_USE_TINYXML
  #define DD4HEP_USE_TINYXML 1
#endif

#define _BACKWARD_BACKWARD_WARNING_H
// Inline headers
//==========================================================================
//  AIDA Detector description implementation
//--------------------------------------------------------------------------
// Copyright (C) Organisation europeenne pour la Recherche nucleaire (CERN)
// All rights reserved.
//
// For the licensing terms see $DD4hepINSTALL/LICENSE.
// For the list of contributors see $DD4hepINSTALL/doc/CREDITS.
//
// Author     : M.Frank
//
//==========================================================================
#ifndef DD4HEP_ALIGMENTS_ALIGNMENTDATA_H
#define DD4HEP_ALIGMENTS_ALIGNMENTDATA_H

// Framework include files
#include "DD4hep/NamedObject.h"
#include "DD4hep/DetElement.h"
#include "DD4hep/Volumes.h"

// ROOT include files
#include "TGeoMatrix.h"

/// Namespace for the AIDA detector description toolkit
namespace dd4hep {

  // Forward declarations
  class Alignment;
  class AlignmentCondition;

  /// Class describing an condition to re-adjust an alignment
  /**
   *
   *  \author  M.Frank
   *  \version 1.0
   *  \ingroup DD4HEP_CONDITIONS
   */
  class Delta   {
  public:
    typedef Translation3D Pivot;
    Position      translation;
    Pivot         pivot;
    RotationZYX   rotation;
    unsigned int  flags = 0;

    enum AlignmentFlags {
      HAVE_NONE         = 0,
...