Fix warnings in uexpect
Fix warnings in uexpect

Ubuntu's standard C compiler hid a few warnings when I was test
compiling uexpect on a x86 netbook. These were reveiled when the
code was compiled using the AVR GCC. Fix up the issues...

Signed-off-by: Martyn Welch <a1c64b5765d2b25c9f71315cb424ca7df21990ee@welchs.me.uk>

mwelchuk/atmel