diff --git a/gdal/port/cpl_port.h b/gdal/port/cpl_port.h
index 98805cf..a6a1846 100644
--- a/gdal/port/cpl_port.h
+++ b/gdal/port/cpl_port.h
@@ -343,7 +343,7 @@ typedef unsigned int  GUIntptr_t;
 #endif
 
 #ifndef CPL_DLL
-#if defined(_MSC_VER) && !defined(CPL_DISABLE_DLL)
+#if defined(WIN32) && (!defined(CPL_DISABLE_DLL) || defined(DLL_EXPORT))
 #  ifdef GDAL_COMPILATION
 #    define CPL_DLL __declspec(dllexport)
 #  else