[pypy-issue] Issue #1988: pypy3: large read will make future os.system calls fail (pypy/pypy)

[Christoph Reiter]

New issue 1988: pypy3: large read will make future os.system calls fail
https://bitbucket.org/pypy/pypy/issue/1988/pypy3-large-read-will-make-future-ossystem

Christoph Reiter:

```
import os
open("/dev/null", "rb").read(4294967295)
print(os.system("true"))
```

prints -1 instead of 0