Problem compiling o2 with system pythia8

Hi all,

when using AliBuild to install o2 I run into problems if pythia8 is installed via package manger. Both, root and o2 compilation fail.
root compilation I solved by adding
to the recipe

the following o2 compilation problem I solved adding
to all find_path and find_library statements in

Perhaps NO_DEFAULT_PATH could have also solved the root compilation, byt I didn’t try.

Not sure if there is a better solution to this, but since it seems we anyhow use pythia8 from alidist I don’t see a problem adding NO_DEFAULT_PATH at least to