The current mapping for STACK_OF(X) and related macros is not ideal, being a combination of the BoringSSL macros on top of the OpenSSL implementation. It does work ok from the perspective of client code, in the sense that BoringSSL code will compile and work ok against the bssl-compat headers. However, the mapping is less than ideal for use in the bssl-compat implementation, requiring a reinterpret_cast<>() to map back and forth. By using the OpenSSL macros, as well as the underlying untyped implementation, should result in an easier to use mapping, and eliminate the need for casting, which in turn will allow more functions to be generated instead of hand written.