[pypy-issue] Issue #2217: Cross-translating cffi modules & unable to execute 'cc' (pypy/pypy)

[mzakharo]

New issue 2217: Cross-translating cffi modules & unable to execute 'cc'
https://bitbucket.org/pypy/pypy/issues/2217/cross-translating-cffi-modules-unable-to

mzakharo:

When cross translating, building the cffi modules with the following command:

```
#!bash
PYTHONPATH=. sb2 -t ARM ./pypy/goal/pypy-c pypy/tool/build_cffi_imports.py
```

fails with the following error:

 unable to execute 'cc': No such file or directory

Attached patch fixes the error for me. 

PYPY version: 4.0.1  
HOST:  
Linux 3.19.0-42-generic 14.04.1-Ubuntu SMP Fri Dec 18 10:24:49 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

TARGET:  
Linux qemuarm 4.1.8-yocto-standard PREEMPT Sun Dec 27 14:53:42 EST 2015 armv5tejl GNU/Linux