headers: Add missing values of MAPPING_ENUM_OPTIONS structure members.

Also add the conditional "extern C" for C++.

Signed-off-by: Biswapriyo Nath <nathbappai@gmail.com>
Signed-off-by: Liu Hao <lh_mouse@126.com>
diff --git a/mingw-w64-headers/include/elscore.h b/mingw-w64-headers/include/elscore.h
index 589fa1e..2e8530a 100644
--- a/mingw-w64-headers/include/elscore.h
+++ b/mingw-w64-headers/include/elscore.h
@@ -8,6 +8,10 @@
 
 #include <objbase.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef ELSCOREAPI
 #define ELSCOREAPI DECLSPEC_IMPORT
 #endif
@@ -16,6 +20,16 @@
 #define CALLBACK WINAPI
 #endif
 
+/* MAPPING_ENUM_OPTIONS.ServiceType */
+#define ALL_SERVICE_TYPES 0
+#define HIGHLEVEL_SERVICE_TYPES 1
+#define LOWLEVEL_SERVICE_TYPES 2
+
+/* MAPPING_ENUM_OPTIONS.OnlineService */
+#define ALL_SERVICES 0
+#define ONLINE_SERVICES 1
+#define OFFLINE_SERVICES 2
+
 typedef struct _MAPPING_DATA_RANGE {
   DWORD  dwStartIndex;
   DWORD  dwEndIndex;
@@ -140,4 +154,8 @@
   DWORD *pdwServicesCount
 );
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /*__INC_ELSCORE__*/