diff --git a/port/cpl_port.h b/port/cpl_port.h
index 9e3ebbb..130af04 100644
--- a/port/cpl_port.h
+++ b/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)
 #  ifdef GDAL_COMPILATION
 #    define CPL_DLL __declspec(dllexport)
 #  else