chore(deps): Bump vendor/bdwgc from 5901d16 to 832713e (#498)

Bumps [vendor/bdwgc](https://github.com/bdwgc/bdwgc) from `5901d16` to
`832713e`.
<details>
<summary>Commits</summary>
<ul>
<li><a
href="832713e82a"><code>832713e</code></a>
GH Actions: Update after prefixing CMake BUILD_SHARED_LIBS option</li>
<li><a
href="382767dcbb"><code>382767d</code></a>
AppVeyor CI: Update after prefixing CMake BUILD_SHARED_LIBS option</li>
<li><a
href="416e4fa765"><code>416e4fa</code></a>
Update AUTHORS file (add Ben Leadbetter)</li>
<li><a
href="e93ee11276"><code>e93ee11</code></a>
Rename CMake BUILD_SHARED_LIBS option to GC_BUILD_SHARED_LIBS</li>
<li>See full diff in <a
href="5901d16bbc...832713e82a">compare
view</a></li>
</ul>
</details>
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Signed-off-by: dependabot[bot] <support@github.com>
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Co-authored-by: Yota Toyama <raviqqe@gmail.com>

build.rs

@@ -59,7 +59,7 @@ fn main() {
 
     let dst = Config::new(LIB_GC_DIR)
         .profile("Release")
-        .define("BUILD_SHARED_LIBS", "FALSE")
+        .define("GC_BUILD_SHARED_LIBS", "FALSE")
         .cflag(format!("-I{}", libatomic_include_path))
         .build();