OpenEXR_CTL on Windows fails due to missing export

I am compiling CTL-1.4.1 which works on windows (unlike the git head 
which chokes on a compiler limitation) and OpenEXR 2.2.
I run into a problem compiling OpenEXR_CTL 1.0.1.  The compilation 
works, but the linking shows:

1>ImfCtlApplyTransforms.obj : error LNK2019: unresolved external symbol 
"class IlmThread_2_2::Mutex & __cdecl Ctl::rcPtrMutex(class 
Ctl::RcObject *)" 
(?rcPtrMutex@Ctl@@YAAEAVMutex@IlmThread_2_2@@PEAVRcObject@1@@Z) 
referenced in function "private: void __cdecl Ctl::RcPtr<class 
Ctl::FunctionArg>::ref(void)" (?ref@?$RcPtr@VFunctionArg@Ctl@@@Ctl@@AEAAXXZ)

1>ImfCtlCopyFunctionArg.obj : error LNK2001: unresolved external symbol 
"class IlmThread_2_2::Mutex & __cdecl Ctl::rcPtrMutex(class 
Ctl::RcObject *)" 
(?rcPtrMutex@Ctl@@YAAEAVMutex@IlmThread_2_2@@PEAVRcObject@1@@Z)

I checked the CtlRcPtr.h/cpp files and the function is defined, but 
never exported.
Any ideas on how to make this work?