Merge pull request #166977 from peperunas/clangMultiStdenv-fix

clangMultiStdenv: expose lib64 and lib separately in sysroot

pkgs/development/compilers/llvm/multi.nix

@@ -19,9 +19,9 @@ let
       lib = gcc_multi_sysroot;
     };
   } ''
-    mkdir -p $out/lib/gcc
+    mkdir -p $out/lib{,64}/gcc
 
-    ln -s ${combine gcc64}/lib/gcc/* $out/lib/gcc/
+    ln -s ${combine gcc64}/lib/gcc/* $out/lib64/gcc/
     ln -s ${combine gcc32}/lib/gcc/* $out/lib/gcc/
     # XXX: This shouldn't be needed, clang just doesn't look for "i686-unknown"
     ln -s $out/lib/gcc/i686-unknown-linux-gnu $out/lib/gcc/i686-pc-linux-gnu