define NS_MSG_BASE which is used as a prefix in front of all functions & classes in base\util. This macro applies to win32 only right now. It is used to declare things as export when building the file and import when we are linking against the file. This helps us make msgcoreutil build as a dynamic library on win32.

mailnews/base/public/msgCore.h

@@ -141,10 +141,28 @@ NS_ERROR_GENERATE_FAILURE(NS_ERROR_MODULE_MAILNEWS, value)
 #  endif /* XP_WIN */
 #endif /* XP_MAC */
 
+
+/* mscott - i'm only turning  NS_MSG_BASE on for windows so
+   define it as empty for the other platforms. */
+
+#ifdef XP_WIN
+
+#ifdef _IMPL_NS_MSG_BASE
+#define NS_MSG_BASE NS_EXPORT
+#else
+#define NS_MSG_BASE NS_IMPORT
+#endif
+
+#else
+#define NS_MSG_BASE
+#endif
+
 ////////////////////////////////////////////////////////////////////////////////
 // Utilities 
 
-extern nsresult
+// mscott: one wouldn't normally have to add the NS_MSG_BASE prefix here 
+// except this function is implemented in base\util.
+nsresult NS_MSG_BASE
 nsGetMailFolderSeparator(nsString& result);
 
 ////////////////////////////////////////////////////////////////////////////////