diff --git a/doc/How to build - Mac OS.md b/doc/How to build - Mac OS.md
index 42a71e10d..b4196909d 100644
--- a/doc/How to build - Mac OS.md	
+++ b/doc/How to build - Mac OS.md	
@@ -20,6 +20,9 @@ You can also customize the bundle output path using the `-DDESTDIR=<some path>`
 **Warning**: Once the dependency bundle is installed in a destdir, the destdir cannot be moved elsewhere.
 (This is because wxWidgets hardcodes the installation path.)
 
+FIXME The Cereal serialization library needs a tiny patch on some old OSX clang installations
+https://github.com/USCiLab/cereal/issues/339#issuecomment-246166717
+
 
 ### Building PrusaSlicer
 
diff --git a/src/libslic3r/Utils.hpp b/src/libslic3r/Utils.hpp
index adf7f57a7..3b30e981c 100644
--- a/src/libslic3r/Utils.hpp
+++ b/src/libslic3r/Utils.hpp
@@ -182,7 +182,7 @@ class ScopeGuard
 public:
     typedef std::function<void()> Closure;
 private:
-    bool committed;
+//    bool committed;
     Closure closure;
 
 public: