From f52b4a268fda27b2e629fed7368f743db0dc9aad Mon Sep 17 00:00:00 2001
From: Trevor Gross <tmgross@umich.edu>
Date: Mon, 6 May 2024 04:26:49 -0500
Subject: [PATCH] Remove the undocumented and unused `rustbuild` feature

See
<https://github.com/rust-lang/compiler-builtins/pull/603#discussion_r1590747361>
---
 library/compiler-builtins/build.rs | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/library/compiler-builtins/build.rs b/library/compiler-builtins/build.rs
index 31e527a0b6a7..47c8b4ffe56a 100644
--- a/library/compiler-builtins/build.rs
+++ b/library/compiler-builtins/build.rs
@@ -375,15 +375,6 @@ mod c {
             ]);
         }
 
-        // When compiling in rustbuild (the rust-lang/rust repo) this library
-        // also needs to satisfy intrinsics that jemalloc or C in general may
-        // need, so include a few more that aren't typically needed by
-        // LLVM/Rust.
-        #[allow(unexpected_cfgs)]
-        if cfg!(feature = "rustbuild") {
-            sources.extend(&[("__ffsdi2", "ffsdi2.c")]);
-        }
-
         // On iOS and 32-bit OSX these are all just empty intrinsics, no need to
         // include them.
         if target_os != "ios"