wxGetInstance must be defined as extern C (patch 1085837)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@31085 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/main.cpp

@@ -155,7 +155,7 @@ DllMain(HANDLE hModule, DWORD fdwReason, LPVOID WXUNUSED(lpReserved))
 
 HINSTANCE wxhInstance = 0;
 
-HINSTANCE wxGetInstance()
+extern "C" HINSTANCE wxGetInstance()
 {
     return wxhInstance;
 }