rustdoc: avoid inlining foreigns with duplicate names

src/test/rustdoc/auxiliary/issue-99734-aux.rs

@@ -5,3 +5,7 @@ impl Option {
 
 /// [`Option::unwrap`]
 pub mod task {}
+
+extern "C" {
+    pub fn main() -> std::ffi::c_int;
+}

src/test/rustdoc/issue-99734-multiple-foreigns-w-same-name.rs

@@ -0,0 +1,16 @@
+// aux-build:issue-99734-aux.rs
+// build-aux-docs
+// ignore-cross-compile
+
+#![crate_name = "foo"]
+
+#[macro_use]
+extern crate issue_99734_aux;
+
+pub use issue_99734_aux::*;
+
+// @count foo/index.html '//a[@class="fn"][@title="foo::main fn"]' 1
+
+extern "C" {
+    pub fn main() -> std::ffi::c_int;
+}