message: Fix out-of-source building with GNU make.
diff: @@ -37,14 +37,13 @@ all: header config-mk
  MPI = $(MFEM_USE_MPI:NO=)
  GHV = get_hypre_version
  -GHV_FLAGS = `printf "%s" "$${HYPRE_OPT}" | \
  - sed -e 's/@MFEM_DIR@/$(if $(MFEM_DIR),$(MFEM_DIR),..)/g'`
  +GHV_FLAGS = $(subst @MFEM_DIR@,$(if $(MFEM_DIR),$(MFEM_DIR),..),$(HYPRE_OPT))
  -get-hypre-version: $(GHV).cpp
  +get-hypre-version: $(SRC)$(GHV).cpp
  $(call mfem-info, Determining HYPRE version ...)
  $(eval MFEM_HYPRE_VERSION:=$(shell \
  - CXXFLAGS=$(GHV_FLAGS) && \
  - $(MFEM_CXX) $${CXXFLAGS} $(GHV).cpp -o $(GHV) > /dev/null 2>&1 && \
  + $(MFEM_CXX) ${GHV_FLAGS} $(SRC)$(GHV).cpp -o $(GHV) \
  + > /dev/null 2>&1 && \
  { ./$(GHV); rm -f $(GHV) > /dev/null 2>&1; }))
  $(if $(MFEM_HYPRE_VERSION),,$(error Unable to determine HYPRE version))
  $(eval export MFEM_HYPRE_VERSION)
  