C++: Add BMN Rust dependency generator

Add a script for generating vendored dependencies for the C++ BMN
extractor. The setup and approach is identical to what we already use
for existing Rust-based extractors.

Author: paldepind

cpp/extractor/bmn/BUILD.bazel

@@ -0,0 +1,4 @@
+exports_files([
+    "Cargo.lock",
+    "Cargo.toml",
+])

cpp/extractor/bmn/Cargo.toml

@@ -1,11 +1,13 @@
+[workspace]
+
 [package]
 name = "bmn"
 version = "0.1.0"
 edition = "2024"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-# when updating, run `./update_cargo_deps.sh` to update bazel bindings
+# When updating, run `misc/bazel/3rdparty/update_cpp_bmn_deps.sh` to update Bazel bindings.
 [dependencies]
 anyhow = "1"
 cached = "0.54"

misc/bazel/3rdparty/BUILD.bazel

@@ -22,3 +22,14 @@ crates_vendor(
     tags = ["manual"],
     vendor_path = "py_deps",
 )
+
+crates_vendor(
+    name = "vendor_cpp_bmn_deps",
+    cargo_lockfile = "//cpp/extractor/bmn:Cargo.lock",
+    generate_build_scripts = True,
+    manifests = ["//cpp/extractor/bmn:Cargo.toml"],
+    mode = "remote",
+    repository_name = "vendor_cpp_bmn",
+    tags = ["manual"],
+    vendor_path = "cpp_bmn_deps",
+)

misc/bazel/3rdparty/update_cargo_deps.sh

@@ -7,3 +7,4 @@ SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 
 "$SCRIPT_DIR/update_py_deps.sh"
 "$SCRIPT_DIR/update_tree_sitter_extractors_deps.sh"
+"$SCRIPT_DIR/update_cpp_bmn_deps.sh"

misc/bazel/3rdparty/update_cpp_bmn_deps.sh

@@ -0,0 +1,11 @@
+#! /usr/bin/env bash
+
+set -eu
+
+WORKSPACE_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )/../../.." &> /dev/null && pwd )
+
+cd "$WORKSPACE_DIR"
+time bazel run //misc/bazel/3rdparty:vendor_cpp_bmn_deps
+# no idea why this is necessary, see https://github.com/bazelbuild/rules_rust/issues/3255
+python3 "$WORKSPACE_DIR/misc/bazel/3rdparty/patch_defs.py" misc/bazel/3rdparty/cpp_bmn_deps/defs.bzl
+bazel mod tidy