2013/5/16 David Bremner <bremner@debian.org>:
> Felipe Contreras <felipe.contreras@gmail.com> writes:
>>
>> Yes. Do you have an old version of notmuch installed?
>>
>
> Yes I do. Hmm. It still seems like a bug to me; shouldn't the include
> paths be ordered to find the right include files first?
>
> d

Well I must accept I haven't spent much time on thinking how to make
extconf.rb perfect.
Excerpt from extconf.rb from bindings/ruby:

find_header('notmuch.h', '../../lib')
find_library('notmuch', 'notmuch_database_create', '../../lib')

Two problems here:
1. The library must be built before the bindings are built otherwise
the installed version is used.
    However the installed version should never be used (or must be
made a non-default option somehow)
2. The library must be built in the source tree. Out-of-source tree
builds will cause extconf.rb to look for the installed version too.
    Not sure whether this is a major concern because I don't know
whether out-of-tree builds are supported by the build system.

Having said that, I will try to have a look at solving these issues
this weekend.
Unfortunately I can't make promises because real-life is killing all
my time lately.

        -alip