Comment (by Roland Haas):

Looking at this carefully, the only reason for this song and dance is to create a file with the list of object files in it. However for the last 14 years GNU make has had a file function

fca11f60 - Create a new function $(file ...) (14 years ago) <Paul Smith>

that does just that (https://www.gnu.org/software/make/manual/html_node/File-Function.html):

The file function allows the makefile to write to or read from a file.

which is intended for exactly this use (from the example in the docs):

program: $(OBJECTS)
        $(file >$@.in,$^)
        $(CMD) $(CMDFLAGS) @$@.in
        @rm $@.in

I have updated the pull request to use this function which avoids the various case distinctions and warnings written to screen.

--
Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2908/cactus-fixed-arg-list-too-long-error