x-window-system-dev for installing X-Window includes?

["Andrew Malcolmson" <andzy@imap.cc>]

I'm attempting to compile the GPLed 2.2.0 beta of TheKompany's Rekall and
the configure script halts with a failed check for 'X includes'. 
Searching aptitude for likely packages sources for X includes (this means
C header files, right?) I found the meta package x-window-system-dev but
this seems to be for installing a complete X window development
environment and really overkill for this.

Is there a more specific package for X includes?

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Andrew Malcolmson