message: In config/sample-runs.sh, add option '-d' that is equivalent to
  setting the variable 'mfem_build_dir'.
diff: @@ -170,6 +170,9 @@ function help_message()
  -v Enable valgrind
  -o <dir> [${output_dir:-"<empty>: output goes to stdout"}]
  If not empty, save output to files inside <dir>
  + -d <dir> [${mfem_build_dir}]
  + If <dir> is different from <mfem_dir> then use an
  + out-of-source build in <dir>
  -j <np> [${make_j}] Specify the number of jobs to use for building
  -c|-color Always use colors for the status messages: OK, FAILED, etc
  -b|-built Do NOT rebuild the library and the executables
  @@ -196,8 +199,8 @@ function help_message()
  Their values can also set using the respective uppercase environment
  variable
  mfem_build_dir [${mfem_build_dir}]
  - Set this variable to something different from <mfem_dir> to use an
  - out-of-source build
  + Same as '-d': set this variable to something different from <mfem_dir>
  + to use an out-of-source build
  For other valid variables, see the script source.
  @@ -266,6 +269,10 @@ case "$1" in
  shift
  output_dir="$1"
  ;;
  + -d)
  + shift
  + mfem_build_dir="$1"
  + ;;
  -j)
  shift
  make_j="-j $1"
  