message: Fix our test for MPIEXEC being binary in case it's not found
diff: @@ -91,7 +91,7 @@ configure_file(
  include (TestSupp.cmake )
  -if (ADIOS2_HAVE_MPI)
  +if (ADIOS2_HAVE_MPI AND NOT ("${MPIEXEC_EXECUTABLE}" STREQUAL "MPIEXEC_EXECUTABLE-NOTFOUND"))
  # we want to know if mpiexec is a shell script or a binary executable
  file(READ ${MPIEXEC_EXECUTABLE} MPIFILEDATA LIMIT 1024 HEX)
  string(LENGTH ${MPIFILEDATA} DATALENGTH)
  