tree d80cd28a33d088717b7e309139751fc7c1e4f2f4
parent 9c20a89bebe9d0ee4175388c0f07b0652600c59f
author David Benjamin <davidben@google.com> 1707952523 -0500
committer Boringssl LUCI CQ <boringssl-scoped@luci-project-accounts.iam.gserviceaccount.com> 1708019664 +0000

Work around bindgen bug around constants

Due to https://github.com/rust-lang/rust-bindgen/issues/923, bindgen
does not evaluate constants correctly. This means arithemetic is done
with the wrong type, and more importantly the output has the wrong type.

Ultimately, this is a bug in bindgen, but as that's remains unfixed,
we'll have to work around it.

rust-openssl's bindgen mode works around this by using the build.rs
bindgen driver and registering a callback to fix the type. This won't
work for some of our consumers, which require a hermetic and
reproducible builds. Instead, apply bssl-sys's workaround at the lib.rs
level. This removes a divergence between bssl-sys and rust-openssl's
bindgen mode.

Fixing these types does not mean we recommending using all of these
constants! Many of the options here are ill-defined or produce even more
ambiguous output than most. XN_FLAG_COMPAT is especially fun because it
change the calling convention! The only option anyone should use is
XN_FLAG_RFC2253, as that's at least a well-defined output.

Fixed: 636
Change-Id: Id34b4a46e0cfd6dcb275477d9bb915bda66c787d
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/66228
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: David Benjamin <davidben@google.com>