Problem with installation of trampoline RTOS

Good evening everyone. I occurred a problem with the installation of Trampoline RTOS on my Mac (to run Arduino). The following link is the link where I kept the installation file: https://github.com/TrampolineRTOS/trampoline.
I proceeded from terminal and what I did is the following passages:

cd trampoline-master/viper
make
cd trampoline-master/goil/makefile-macosx/
./build.py
export VIPER_PATH=/trampoline-master/viper
cd trampoline-master/examples/posix/periodic
goil --target=posix/darwin --templates=…/…/…/goil/templates/ periodic.oil
./build.py
./periodic_exe

At this point the following message compared:

VIPER_PATH is defined but viper is not accessible or executable Exiting virtual platform.

Anyone knows how I can solve my problem? Any kind of help would be very useful.
Thank you very much.