gcc not found (includes fix)

```
Hi,

i was getting an error when using the toolchain file that gcc was not found.

Can you please replace:

CMAKE_FORCE_C_COMPILER (gcc gcc)
CMAKE_FORCE_CXX_COMPILER (g++ g++)

with

CMAKE_FORCE_C_COMPILER (/usr/bin/gcc gcc)
CMAKE_FORCE_CXX_COMPILER (/usr/bin/g++ g++)

That fixed it for me.

Thanks in advance.

Cheers,

Ben
```

Original issue reported on code.google.com by `benjamin...@gmail.com` on 23 Jul 2015 at 9:45