Run make SGX=1 or make in the directory. Gramine is required, but SGX is not required to build.
Note the makefile builds scripts/hello.c as an elf binary
First the obvious way
python3 scripts/execve.py
Then run with the gramine loader
gramine-direct python scripts/execve.py
Finally the real deal with SGX
gramine-sgx python scripts/execve.py