Added extern "C" if __cplusplus is defined.

diff --git a/include/ddraw.h b/include/ddraw.h
index fbf5582..03ef896 100644
--- a/include/ddraw.h
+++ b/include/ddraw.h
@@ -10,6 +10,10 @@
 #include "wingdi.h" /* PALETTE stuff ... */
 #include "wine/obj_base.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif /* defined(__cplusplus) */
+
 #ifndef	DIRECTDRAW_VERSION
 #define	DIRECTDRAW_VERSION	0x0500
 #endif /* DIRECTDRAW_VERSION */
@@ -1509,4 +1513,8 @@
 #define DirectDrawEnumerate WINELIB_NAME_AW(DirectDrawEnumerate)
 HRESULT WINAPI DirectDrawCreateClipper(DWORD,LPDIRECTDRAWCLIPPER*,LPUNKNOWN);
 
+#ifdef __cplusplus
+} /* extern "C" */
+#endif /* defined(__cplusplus) */
+
 #endif /* __WINE_DDRAW_H */