stdenv bootstrap: hack around glibc version mismatch

With this we shouldn't need other workarounds for the LTO problems.

pkgs/stdenv/linux/default.nix

@@ -258,6 +258,25 @@ in
         # Rewrap the binutils with the new glibc, so both the next
         # stage's wrappers use it.
         libc = getLibc self;
+
+        # Unfortunately, when building gcc in the next stage, its LTO plugin
+        # would use the final libc but `ld` would use the bootstrap one,
+        # and that can fail to load.  Therefore we upgrade `ld` to use newer libc;
+        # apparently the interpreter needs to match libc, too.
+        bintools = self.stdenvNoCC.mkDerivation {
+          inherit (prevStage.bintools.bintools) name;
+          dontUnpack = true;
+          dontBuild = true;
+          # We wouldn't need to *copy* all, but it's easier and the result is temporary anyway.
+          installPhase = ''
+            mkdir -p "$out"/bin
+            cp -a '${prevStage.bintools.bintools}'/bin/* "$out"/bin/
+            chmod +w "$out"/bin/ld.bfd
+            patchelf --set-interpreter '${getLibc self}'/lib/ld*.so.? \
+              --set-rpath "${getLibc self}/lib:$(patchelf --print-rpath "$out"/bin/ld.bfd)" \
+              "$out"/bin/ld.bfd
+          '';
+        };
       };
     };
   })