Put Rust binding generation behind an explicit flag and only build bindings for the targeted Arch
Change-Id: I8ccd53bce0d73bd9d79f65770e544a75753ce4f8
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/51025
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/rust/README.md b/rust/README.md
index 271d4d5..fb5230a 100644
--- a/rust/README.md
+++ b/rust/README.md
@@ -4,5 +4,10 @@
A low-level binding crate for Rust that moves in lockstop with BoringSSL. BoringSSL explicitly does not have a stable ABI, `bssl-sys` is the solution for preventing subtle-memory corruption bugs due to version skew.
### How it works
-`bssl-sys` uses `bindgen` as part of the cmake build process to generate Rust compatibility shims for each supported target platform. It is important to generate it for each platform because `bindgen` uses LLVM information for alignment which varies depending on architecture. These files are then packaged into a Rust crate.
+`bssl-sys` uses `bindgen` as part of the cmake build process to generate Rust compatibility shims for the targeted platform. It is important to generate it for the correct platform because `bindgen` uses LLVM information for alignment which varies depending on architecture. These files are then packaged into a Rust crate.
+
+### To Use
+Build `boringssl` with `-DRUST_BINDINGS=<rust-triple>` and ensure that you have `bindgen` installed.
+
+The `rust-triple` option should be one of the supported targets at https://doc.rust-lang.org/nightly/rustc/platform-support.html.
