Fix build.sh mode and line-endings

build.sh was missing the +x bit and linux didn't like the dos line-endings.

    $ make
    make: execvp: ./build.sh: Permission denied
    $ chmod +x build.sh
    $ make
    make: ./build.sh: Command not found
    $./build.sh 
    bash: ./build.sh: /bin/bash^M: bad interpreter: No such file or directory