#10 type mismatch in emx_usb.c

[brodie]

The prototype declaration of function 'static ssize_t
emx_read(...)' is different to the function itself,
here: 'static int emx_read(...)'.

On my 64 bit machine with Suse 10.0 (kernel
2.6.13-15.8) this results in a compiler error. Have
changed the code to 'ssize_t' and now it works fine on
my Eumex 504 PC USB.

You guys did a good job. Thanx for the fine software!!!