message: add again CXX argument to mpicxx (to get for sure C++11 compiler)
diff: @@ -94,8 +94,8 @@ pipeline {
  steps {
  setupCC()
  sh "echo > make/local"
  - sh "echo CC=${env.MPICXX} >> make/local"
  - sh "echo CXX=${env.MPICXX} >> make/local"
  + sh "echo CC=${env.MPICXX} -cxx=${env.CXX} >> make/local"
  + sh "echo CXX=${env.MPICXX} -cxx=${env.CXX} >> make/local"
  sh "echo STAN_MPI=true >> make/local"
  sh runTests("./")
  }
  