Merge pull request #237 from pinoOgni/install-documentation

Added warning llvm 6 in install documentation

Author: frisso

Documentation/installation.rst

@@ -56,6 +56,12 @@ In this case you have to:
 
 Once the installation is completed, you can follow the :doc:`quickstart` instructions.
 
+Note: if you have llvm 6.0 installed (check with ``apt list --installed | grep "llvm"``), the installation script will fail.
+In this case, remove llvm 6.0 before starting the installation script:
+
+::
+    sudo apt remove llvm-6.0 llvm-6.0-dev llvm-6.0-runtime
+
 Installing from source
 ----------------------