configure script fails when executed from ZSH

[Thomsch]

The instructions specify to use source experiment/configure to launch the experiment.

If the participant uses ZSH, the script fails because BASH_SOURCE[0] variable is not set which breaks path resolution in configure but also in setup.sh.

A workaround is to temporarily deactivate ZSH by typing bash in the terminal. However, this solution might be confusing to integrate into the instructions in the eventuality a participant uses ZSH.

My main idea to solve this issue is to update configure to force the use of Bash. The problem with this solution is that we're using source to run the script instead of simply executing ./configure where the bash shebang would take care of it (it is already present). I'm unsure how I would go about solving this issue.