[PATCH v2] fix out of tree build

[David Bremner]

Tomi Ollila <tomi.ollila at iki.fi> writes:

> With working tests.
> ---
>
> This is v2 of id:1479066903-28310-1-git-send-email-tomi.ollila at iki.fi
>
> with this ${srcdir} being absolute path will also work (relevant in tests!)
>
> ... and commit message is fixed: I accuse qt for "shadow build" ;)
>
> Out of tree builds breaks every now and then; perhaps it is broken less
> often in the future as I plan to start doing my "production" builds
> out of tree...

Hi Tomi;

Did you test this with ruby-dev installed? for me out-of-tree-build
fails with your patch with

cd bindings/ruby && \
	EXTRA_LDFLAGS="-Wl,--no-undefined" \
	LIBNOTMUCH="../../lib/libnotmuch.so" \
	ruby extconf.rb --vendor
/bin/sh: 1: cd: can't cd to bindings/ruby
bindings/Makefile.local:8: recipe for target 'ruby-bindings' failed