diff --git a/dll/win32/twain_32/twain32_main.c b/dll/win32/twain_32/twain32_main.c
index b1beb969580..0f8ee144306 100644
--- a/dll/win32/twain_32/twain32_main.c
+++ b/dll/win32/twain_32/twain32_main.c
@@ -29,7 +29,9 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(twain);
 
-extern HINSTANCE DSM_hinstance;
+TW_UINT16 DSM_twCC;
+activeDS *activeSources;
+HINSTANCE DSM_hinstance;
 
 BOOL WINAPI DllMain (HINSTANCE hinstance, DWORD reason, LPVOID reserved)
 {
diff --git a/dll/win32/twain_32/twain_i.h b/dll/win32/twain_32/twain_i.h
index 7939d233bb0..fb3a4ec1a65 100644
--- a/dll/win32/twain_32/twain_i.h
+++ b/dll/win32/twain_32/twain_i.h
@@ -45,11 +45,11 @@ typedef struct tagActiveDS
     HWND                event_window;
 } activeDS;
 
-TW_UINT16 DSM_twCC DECLSPEC_HIDDEN;             /* current condition code of Source Manager */
+extern TW_UINT16 DSM_twCC DECLSPEC_HIDDEN;             /* current condition code of Source Manager */
 
-activeDS *activeSources DECLSPEC_HIDDEN;	/* list of active data sources */
+extern activeDS *activeSources DECLSPEC_HIDDEN; /* list of active data sources */
 
-HINSTANCE DSM_hinstance DECLSPEC_HIDDEN;
+extern HINSTANCE DSM_hinstance DECLSPEC_HIDDEN;
 
 /* Implementation of operation triplets (From Application to Source Manager) */
 extern TW_UINT16 TWAIN_CloseDS