message: Have the mpi module re-open itself with `RTLD_NOLOAD` to promote symbols
  This resolves the OpenMPI issue with the library symbols not being
  available
diff: #include "common/Data.h"
  #include "common/Library.h"
  #include "common/Util.h"
  +#include "ospcommon/sysinfo.h"
  +#include "ospcommon/FileName.h"
  #include "geometry/TriangleMesh.h"
  #include "render/Renderer.h"
  #include "camera/Camera.h"
  // std
  #ifndef _WIN32
  # include <unistd.h> // for fork()
  +# include <dlfcn.h>
  #endif
  @@ -1132,8 +1135,21 @@ namespace ospray {
  } // ::ospray::mpi
  } // ::ospray
  -extern "C" OSPRAY_DLLEXPORT void ospray_init_module_mpi()
  -{
  +extern "C" OSPRAY_DLLEXPORT void ospray_init_module_mpi() {
  +#ifndef _WIN32
  + using namespace ospcommon;
  +#if defined(__MACOSX__)
  + const std::string fullName = "libospray_module_mpi.dylib";
  +#else
  + const std::string fullName = "libospray_module_mpi.so";
  +#endif
  + void *lib = dlopen(fullName.c_str(), RTLD_NOW | RTLD_NOLOAD | RTLD_GLOBAL);
  + if (!lib) {
  + FileName executable = getExecutableFileName();
  + lib = dlopen((executable.path() + fullName).c_str(), RTLD_NOW | RTLD_NOLOAD | RTLD_GLOBAL);
  + }
  + Assert(lib);
  +#endif
  std::cout << "#mpi: initializing ospray MPI plugin" << std::endl;
  }
  