message: In 'make info', print an MFEM version string (e.g. "v3.3") in addition
  to the integer version (e.g. "30300").
diff: # The current MFEM version as an integer, see also `CMakeLists.txt`.
  MFEM_VERSION = 30300
  +MFEM_VERSION_STRING = $(shell printf "%06s" $(MFEM_VERSION) | \
  + sed -e 's/^0*\(.*.\)\(..\)\(..\)$$/\1.\2.\3/' -e 's/\.0/./g' -e 's/\.0$$//')
  define MFEM_HELP_MSG
  @@ -392,7 +394,7 @@ help:
  @true
  status info:
  - $(info MFEM_VERSION = $(MFEM_VERSION))
  + $(info MFEM_VERSION = $(MFEM_VERSION) [v$(MFEM_VERSION_STRING)])
  $(info MFEM_USE_MPI = $(MFEM_USE_MPI))
  $(info MFEM_USE_METIS_5 = $(MFEM_USE_METIS_5))
  $(info MFEM_DEBUG = $(MFEM_DEBUG))
  