fix dialog plugin to work on windows

include/mysql/client_plugin.h

@@ -28,6 +28,16 @@
 #include <stdlib.h>
 #endif
 
+#if defined(_MSC_VER)
+  #ifdef __cplusplus
+    #define MYSQL_PLUGIN_EXPORT extern "C" __declspec(dllexport)
+  #else
+    #define MYSQL_PLUGIN_EXPORT __declspec(dllexport)
+  #endif
+#else /*_MSC_VER */
+#define MYSQL_PLUGIN_EXPORT
+#endif
+
 /* known plugin types */
 #define MYSQL_CLIENT_reserved1               0
 #define MYSQL_CLIENT_reserved2               1
@@ -38,6 +48,7 @@
 #define MYSQL_CLIENT_MAX_PLUGINS             3
 
 #define mysql_declare_client_plugin(X)          \
+     MYSQL_PLUGIN_EXPORT                        \
      struct st_mysql_client_plugin_ ## X        \
         _mysql_client_plugin_declaration_ = {   \
           MYSQL_CLIENT_ ## X ## _PLUGIN,        \

include/mysql/plugin_auth_common.h

@@ -14,6 +14,10 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
 /**
   @file