message: define CXX as well in make/local during testing on Jenkins with MPI
diff: @@ -93,8 +93,9 @@ pipeline {
  agent any
  steps {
  setupCC()
  - sh "echo >> make/local"
  + sh "echo > 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("./")
  }
  