<multibuild>
  <package>documentation</package>
  <package>documentation-hpc</package>
  <package>serial</package>
  <package>openmpi2</package>
  <package>openmpi4</package>
  <package>gnu-openmpi2-hpc</package>
  <package>gnu-openmpi3-hpc</package>
  <package>gnu-openmpi4-hpc</package>
  <package>gnu-mvapich2-hpc</package>
  <package>gnu-mpich-hpc</package>
</multibuild>