$ ksh configure
Welcome to Notmuch, a system for indexing, searching and tagging your email.

We hope that the process of building and installing notmuch is quick
and smooth so that you can soon be reading and processing your email
more efficiently than ever.

If anything goes wrong in the configure process, you can override any
decisions it makes by manually editing the Makefile.config file that
it creates. Also please do as much as you can to figure out what could
be different on your machine compared to those of the notmuch
developers. Then, please email those details to the Notmuch list
(notmuch@notmuchmail.org) so that we can hopefully make future
versions of notmuch easier for you to use.

We'll now investigate your system to verify that all required
dependencies are available:

Sanity checking C compilation environment... OK.
Sanity checking C++ compilation environment... OK.
Reading libnotmuch version from source...
*** Error: Reading lib/notmuch.h failed.
Please try running configure again in a clean environment, and if the
problem persists, report a bug.