Previously, we were building the final binary with this option, but not
the library. The library can benefit from it as well, (as pointed out
by Debian's lintian).
ifeq ($(LIBDIR_IN_LDCONFIG),0)
FINAL_NOTMUCH_LDFLAGS += $(RPATH_LDFLAGS)
endif
-FINAL_LIBNOTMUCH_LDFLAGS = $(LDFLAGS) $(CONFIGURE_LDFLAGS)
+FINAL_LIBNOTMUCH_LDFLAGS = $(LDFLAGS) $(CONFIGURE_LDFLAGS) $(AS_NEEDED_LDFLAGS)
.PHONY: all
all: notmuch notmuch-shared notmuch.1.gz