GnuWin32 corrections (::ZeroMemory doesn't exist)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@1695 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/utilsexc.cpp

@@ -211,7 +211,12 @@ long wxExecute(const wxString& command, bool sync, wxProcess *handler)
 #else // 1
     // create the process
     STARTUPINFO si;
+#ifdef __GNUWIN32__
+    memset(&si, 0, sizeof(si));
+#else
     ::ZeroMemory(&si, sizeof(si));
+#endif
+
     si.cb = sizeof(si);
 
     PROCESS_INFORMATION pi;