nixpkgs/pkgs/development/tools/boost-build/darwin-default-toolset.patch

diff --git a/src/build-system.jam b/src/build-system.jam
index 60425c54..c6842217 100644
--- a/src/build-system.jam
+++ b/src/build-system.jam
@@ -644,7 +644,7 @@ local rule should-clean-project ( project )
             }
             else if [ os.name ] = MACOSX
             {
-                default-toolset = darwin ;
+                default-toolset = clang-darwin ;
             }
         }