first round of Intel compiler warning fixes: down from a few thousands just to slightly more than 100

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@35688 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/app.h

@@ -661,6 +661,7 @@ public:
     }                                                                       \
     wxAppInitializer                                                        \
         wxTheAppInitializer((wxAppInitializerFunction) wxCreateApp);        \
+    DECLARE_APP(appname)                                                    \
     appname& wxGetApp() { return *(appname *)wxTheApp; }
 
 // Same as IMPLEMENT_APP() normally but doesn't include themes support in
@@ -684,5 +685,13 @@ public:
 // function
 #define DECLARE_APP(appname) extern appname& wxGetApp();
 
+
+// declare the stuff defined by IMPLEMENT_APP() macro, it's not really needed
+// anywhere else but at the very least it suppresses icc warnings about
+// defining extern symbols without prior declaration, and it shouldn't do any
+// harm
+extern wxAppConsole *wxCreateApp();
+extern wxAppInitializer wxTheAppInitializer;
+
 #endif // _WX_APP_H_BASE_