rustc: don't strip bootstrap on darwin

pkgs/development/compilers/rust/binary.nix

@@ -52,6 +52,12 @@ rec {
       # https://github.com/rust-lang/rust/issues/34722#issuecomment-232164943
     '';
 
+    # The strip tool in cctools 973.0.1 and up appears to break rlibs in the
+    # binaries. The lib.rmeta object inside the ar archive should contain an
+    # .rmeta section, but it is removed. Luckily, this doesn't appear to be an
+    # issue for Rust builds produced by Nix.
+    dontStrip = stdenv.isDarwin;
+
     setupHooks = ./setup-hook.sh;
   };