Missing Dependencies

[lanodan]

Looks like you forgot:

• threads
• gtest

Also you can see in #66 the configure part(meson) finishes without errors while xapian isn’t installed (and so detected). If there is optional dependencies please say so.

[mgautierfr]

threads is a generic name for meson to identify the "thread library".
This threading library may change depending of the system. (On linux, it is pthread, who is part of glibc).
This is not a "real" dependency as it is provided by the standard libc and there is nothing to install (but the libc)

gtest was using meson subproject. So it was not needed to have it installed.
I've recently change about this to use the system one if meson find it or use the subproject else.
I've added gtest dependency to the README.

I've also added to README the fact that xapian is optional.