diff --git a/src/cmake/externalpackages.cmake b/src/cmake/externalpackages.cmake
index 0ca1fe6..1eeb5ab 100644
--- a/src/cmake/externalpackages.cmake
+++ b/src/cmake/externalpackages.cmake
@@ -105,7 +105,7 @@ checked_find_package (OpenEXR REQUIRED
 # building against Imath/OpenEXR 3.x when there is still a system-level
 # install version of 2.x.
 include_directories(BEFORE ${IMATH_INCLUDES} ${OPENEXR_INCLUDES})
-if (MSVC AND NOT LINKSTATIC)
+if (WIN32 AND BUILD_SHARED_LIBS)
     add_definitions (-DOPENEXR_DLL) # Is this needed for new versions?
 endif ()
 if (OpenEXR_VERSION VERSION_GREATER_EQUAL 3.0)