diff --git a/netwerk/base/public/netCore.h b/netwerk/base/public/netCore.h
index 6db21abe648..24e632db1d4 100644
--- a/netwerk/base/public/netCore.h
+++ b/netwerk/base/public/netCore.h
@@ -48,13 +48,13 @@
 
 #undef NS_NET
 #ifdef _IMPL_NS_NET
-#ifdef XP_PC
+#if defined(XP_PC) && !defined(XP_OS2)
 #define NS_NET _declspec(dllexport)
 #else  /* !XP_PC */
 #define NS_NET
 #endif /* !XP_PC */
 #else  /* !_IMPL_NS_NET */
-#ifdef XP_PC
+#if defined(XP_PC) && !defined(XP_OS2)
 #define NS_NET _declspec(dllimport)
 #else  /* !XP_PC */
 #define NS_NET