File _multibuild of Package scotch

<multibuild>
  <package>serial</package>
  <package>openmpi4</package>
  <package>mvapich2</package>
  <package>mpich</package>
  <package>gnu-hpc</package>
  <package>gnu-openmpi4-hpc</package>
  <package>gnu-mvapich2-hpc</package>
  <package>gnu-mpich-hpc</package>
</multibuild>