autocxx-build: Re-export result types used in API

Without these, users' build scripts have no way to refer to the result
type by name, meaning they can't rewrap or inspect the error. I'm
guessing most users use miette like the documentation suggests, which
avoids the issue, but we should still support other use cases.

Author: tchebb

gen/build/src/lib.rs

@@ -12,6 +12,8 @@ use autocxx_engine::{BuilderContext, RebuildDependencyRecorder};
 use indexmap::set::IndexSet as HashSet;
 use std::{io::Write, sync::Mutex};
 
+pub use autocxx_engine::{BuilderError, BuilderSuccess};
+
 pub type Builder = autocxx_engine::Builder<'static, CargoBuilderContext>;
 
 #[doc(hidden)]