<mutex> error is not supported when compiling with / clr or / clr: pure

I have a C ++ dll which I will call Dll A where I used:

#include <mutex>

      

        
        
        
      

    

Dll Properties set to No Common Language Time Support and it succeeds.

I have another Dll B that includes DLL A in its links. The Bs Dll properties are set to "Common Language Runtime Support (/ clr)" because it includes C ++ / CLI code.

When I create DLL B I get the error: C: \ Program Files (x86) \ Microsoft Visual Studio 11.0 \ VC \ include \ mutex (8): fatal error C1189: #error: <mutex> not supported when compiling with / clr or / clr: pure.

I know I can't include in the CLR-enabled DLL, but is there a way to get around this issue to reference the DLL that includes it?