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

[David Bremner]

In 40b025 we stopped building the notmuch-emacs documentation if
HAVE_EMACS=0 (i.e. no emacs was detected by configure). Unfortunately
we continued to try to install the (non-existent) documentation, which
causes build/install failures.

As a bonus, we also avoid installing the documentation if the user
configures --without-emacs.

We use '$(if )' instead of 'ifeq' here (and change ':=' to '=') to
make sure that WITH_EMACS and HAVE_EMACS are defined before we expand
INFO_TEXI_FILES.

Thanks to Ralph Seichter for reporting the problem, and testing
previous versions of this fix.
---
 doc/Makefile.local | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/doc/Makefile.local b/doc/Makefile.local
index 719172fe..92c41b57 100644
--- a/doc/Makefile.local
+++ b/doc/Makefile.local
@@ -28,7 +28,9 @@ MAN_GZIP_FILES := $(addsuffix .gz,${MAN_ROFF_FILES})
 MAN1_TEXI := $(patsubst $(srcdir)/doc/man1/%.rst,$(DOCBUILDDIR)/texinfo/%.texi,$(MAN1_RST))
 MAN5_TEXI := $(patsubst $(srcdir)/doc/man5/%.rst,$(DOCBUILDDIR)/texinfo/%.texi,$(MAN5_RST))
 MAN7_TEXI := $(patsubst $(srcdir)/doc/man7/%.rst,$(DOCBUILDDIR)/texinfo/%.texi,$(MAN7_RST))
-INFO_TEXI_FILES := $(MAN1_TEXI) $(MAN5_TEXI) $(MAN7_TEXI) $(DOCBUILDDIR)/texinfo/notmuch-emacs.texi
+INFO_TEXI_FILES = $(MAN1_TEXI) $(MAN5_TEXI) $(MAN7_TEXI) \
+	$(if $(filter 11,$(HAVE_EMACS)$(WITH_EMACS)), $(DOCBUILDDIR)/texinfo/notmuch-emacs.texi,)
+
 INFO_INFO_FILES := $(INFO_TEXI_FILES:.texi=.info)
 
 .PHONY: sphinx-html sphinx-texinfo sphinx-info
-- 
2.20.1