I have made a variable so that users can pass --split=chapter.
Doing so with conditional to save value in variable decal.
If empty, I keep its value empty. Is this the correct way,
does make accept variables starting with --?
.PHONY: --all-doc --info --html --pdf --dvi --ps
--all-doc: --info --html --pdf --dvi --ps
--info: ${infdir}/antares.info
--html: ${hmldir}/antares.html
--pdf: ${docdir}/antares.pdf
--dvi: ${docdir}/antares.dvi
--ps: ${docdir}/antares.ps
ifeq ($(--split),)
decal=
else
decal=--split=$(split)
endif
.SECONDEXPANSION:
$(hmldir)/antares.html: $(srcs) | $$(@D)
makeinfo $(opts) --html $(decal) -o $@ $<
