After a succesful configure, make exits with *snipped*

```
gclosure.c:29:17: fatal error: ffi.h: No such file or directory
compilation terminated.

```

I have libffi installed, and locate ffi.h gives:

```
/home/luca/gcc4.6/gcc-4.6.0/libffi/include/ffi.h.in
/usr/include/x86_64-linux-gnu/ffi.h
/usr/share/doc/ghc-doc/html/users_guide/ffi.html
/usr/share/doc/libffi5/html/Using-libffi.html

```