diff --git a/PyIlmBase/config/ModuleDefine.cmake b/PyIlmBase/config/ModuleDefine.cmake
index 57e2eaf1e7..a127ecba1d 100644
--- a/PyIlmBase/config/ModuleDefine.cmake
+++ b/PyIlmBase/config/ModuleDefine.cmake
@@ -23,19 +23,21 @@ function(PYILMBASE_ADD_LIBRARY_PRIV libname)
     OUTPUT_NAME "${PYILMBASE_CURLIB_OUTROOT}${libname}${PYILMBASE_LIB_SUFFIX}"
   )
   target_compile_features(${libname} PUBLIC cxx_std_${OPENEXR_CXX_STANDARD})
-  if(PYILMBASE_CURLIB_PRIV_EXPORT AND BUILD_SHARED_LIBS)
+  # we are always building shared, so don't check for that
+  if(PYILMBASE_CURLIB_PRIV_EXPORT)
     target_compile_definitions(${libname} PRIVATE ${PYILMBASE_CURLIB_PRIV_EXPORT})
-    if(WIN32)
-      target_compile_definitions(${libname} PUBLIC OPENEXR_DLL)
-    endif()
   endif()
+  target_compile_definitions(${libname} PUBLIC OPENEXR_DLL)
+
   if(PYILMBASE_CURLIB_CURDIR)
     target_include_directories(${libname} PUBLIC $<BUILD_INTERFACE:${PYILMBASE_CURLIB_CURDIR}>)
   endif()
   if(PYILMBASE_CURLIB_CURBINDIR)
     target_include_directories(${libname} PRIVATE $<BUILD_INTERFACE:${PYILMBASE_CURLIB_CURBINDIR}>)
   endif()
-  target_include_directories(${libname} PUBLIC ${Boost_INCLUDE_DIR})
+  if(Boost_INCLUDE_DIR)
+    target_include_directories(${libname} PUBLIC ${Boost_INCLUDE_DIR})
+  endif()
   target_link_libraries(${libname} PUBLIC ${PYILMBASE_CURLIB_DEPENDENCIES})
   if(PYILMBASE_CURLIB_PRIVATE_DEPS)
     target_link_libraries(${libname} PRIVATE ${PYILMBASE_CURLIB_PRIVATE_DEPS})