[PATCH] doc: Don't install emacs docs when they are not built

[David Bremner]

Tomi Ollila <tomi.ollila at iki.fi> writes:
>
> Interestingly, in your commit message you mention that changing := to =
> makes a difference. I would have thought that assigning INFO_INFO_FILES
> with := would have expanded INFO_TEXI_FILES just 2 lines below after
> its introduction. 

Ah. Silly me. The non-working version had the following line in it

    $(INFO_TEXI_FILES):= $(INFO_TEXI_FILES) $(DOCBUILDDIR)/texinfo/notmuch-emacs.texi

The reason that does have _something_ do with variable expansion, just
not what I claimed ;). I think I'll go back to the ifeq version, it's more
like what we use other places.

d