FindMPI: add common paths and MPI releases

Modules/FindMPI.cmake

@@ -339,6 +339,10 @@ set(_MPI_Cray_C_COMPILER_NAMES             cc)
 set(_MPI_Cray_CXX_COMPILER_NAMES           CC)
 set(_MPI_Cray_Fortran_COMPILER_NAMES       ftn)
 
+# Common releases and locations, for cases where MPI is installed by not in $PATH
+set(_MPI_COMMON_RELEASES                   openmpi mpich mvapich2 mvapich)
+set(_MPI_COMMON_LOCATIONS                  /usr/lib /usr/lib64 /usr/local)
+
 # Prepend vendor-specific compiler wrappers to the list. If we don't know the compiler,
 # attempt all of them.
 # By attempting vendor-specific compiler names first, we should avoid situations where the compiler wrapper
@@ -1344,6 +1348,15 @@ elseif("${CMAKE_HOST_SYSTEM_NAME}" STREQUAL "FreeBSD")
   MPI_search_mpi_prefix_folder("/usr/local/mpi")
 endif()
 
+# This macro enumerates installations of an MPI release in common locations on the system
+foreach(_MPI_release_name IN LISTS _MPI_COMMON_RELEASES)
+  foreach(_MPI_folder_prefix IN LISTS _MPI_COMMON_LOCATIONS)
+    if(IS_DIRECTORY "${_MPI_folder_prefix}/${_MPI_release_name}")
+      list(APPEND MPI_HINT_DIRS "${_MPI_folder_prefix}/${MPI_RELEASE}")
+    endif()
+  endforeach()
+endforeach()
+
 # Most MPI distributions have some form of mpiexec or mpirun which gives us something we can look for.
 # The MPI standard does not mandate the existence of either, but instead only makes requirements if a distribution
 # ships an mpiexec program (mpirun executables are not regulated by the standard).