Comment (by Roland Haas):

Adding what I apparently forgot to post: the reason this happens is the the currently used rules by ExternalLibraries look like this:

$(UTIL_DIR)/%: $(MPI_DIR)/bin/%
    @echo "Copying $* from $< to $(UTIL_DIR)"
    -$(MKDIR) $(MKDIRFLAGS) $(UTIL_DIR) 2> /dev/null
    cp $< $@

it a pattern-rule that says that if you need to build % you can build it assuming you have $(MPI_DIR)/bin/%. Now if $(MPI_DIR)/bin contains a file hwloc-info then make will happily run this recipe instead of say the one that has $(HWLOC_DIR)/bin/%.

The fix (above) is to make the rules more specific.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/1923/make-utils-and-simfactory-ignore-hwloc