if [[ $OS = "Darwin" ]]; then
    android_path="$HOME/android-sdk-macosx"
fi

if [[ (-n $android_path) && (-d $android_path) ]]; then
    __append-path-entry $android_path/platform-tools
    __append-path-entry $android_path/tools
fi

unset android_path

if [ $OS = "Darwin" ]; then
    android_path="$HOME/android-sdk-macosx"
fi

if [[ (-n $android_path) && (-d $android_path) ]]; then
    __append-path-entry $android_path/platform-tools
    __append-path-entry $android_path/tools
fi

unset android_path

Change test for path to use POSIX-compliant form
Change test for path to use POSIX-compliant form

I haven't been able to figure out the syntax for the other test.
Leaving it for now.
