Macro btlib::suppress_err_if_non_zero

macro_rules! suppress_err_if_non_zero {
    ($count:expr, $result:expr) => { ... };
}

Attempts to unwrap the given result. If the result is an error and the given count is positive, then the error is logged and Ok($count) is returned. If the result is an error and count is zero, then the Err variant is returned containing it.