On Sun, Mar 1, 2015 at 6:45 AM, Alexander Genaud
# cabal install xmonad-contrib Resolving dependencies... Configuring X11-1.6.1.2... ...etc... checking X11/extensions/Xinerama.h usability... no checking X11/extensions/Xinerama.h presence... no checking for X11/extensions/Xinerama.h... no WARNING: Xinerama headers not found. Building without Xinerama support checking X11/extensions/Xrandr.h usability... no checking X11/extensions/Xrandr.h presence... no checking for X11/extensions/Xrandr.h... no configure: error: X11/extensions/Xrandr.h (from libXrandr) is required Failed to install X11-1.6.1.2 cabal: Error: some packages failed to install: X11-1.6.1.2 failed during the configure step. The exception was: ExitFailure 1
You will need the development version of that library installed. In Debian-alikes, the development versions of library packages have names ending with -dev. ~d