Evaluating a long list with eval() causes segfault.

See the following example, we take a long computation of list addition operation. RustPython crashes.

test.py

mylist = []
n = 10000
print(eval("mylist"+"+mylist"*n))

Actual output:

Segmentation fault (core dumped)

System:

Ubuntu 16.04
Rust Python 0.1.2 interpreter