luasocket: config files should use $(CC) not gcc

In 32bit mode we override CC to `gcc -m32` which is how we pass down the
-m32 flag but that's being ignored because the config is not allowing us
to set CC our selves and instead was hard coded to gcc.

We could enable the -e option to make but then that would override all
the settings we have in the config files so that's not good option...