Remove checks for outdated GCC versions

wxWidgets now supports only GCC 4 and newer, so there is no reason
to keep code specific for older GCC versions.

include/wx/cpp.h

@@ -140,20 +140,6 @@
 
 #ifdef HAVE_VARIADIC_MACROS
 
-/*
-   This is a hack to make it possible to use variadic macros with g++ 3.x even
-   when using -pedantic[-errors] option: without this, it would complain that
-
-       "anonymous variadic macros were introduced in C99"
-
-   and the option disabling this warning (-Wno-variadic-macros) is only
-   available in gcc 4.0 and later, so until then this hack is the only thing we
-   can do.
- */
-#if defined(__GNUC__) && __GNUC__ == 3
-    #pragma GCC system_header
-#endif /* gcc-3.x */
-
 /*
    wxCALL_FOR_EACH(what, ...) calls the macro from its first argument, what(pos, x),
    for every remaining argument 'x', with 'pos' being its 1-based index in

include/wx/msw/gccpriv.h

@@ -77,9 +77,7 @@
         #define HAVE_W32API_H
     #endif
 #elif defined( __CYGWIN__ ) && !defined( HAVE_W32API_H )
-    #if ( __GNUC__ > 2 )
-        #define HAVE_W32API_H
-    #endif
+    #define HAVE_W32API_H
 #endif
 
 /* check for MinGW/Cygwin w32api version ( releases >= 0.5, only ) */

include/wx/platform.h

@@ -332,10 +332,6 @@
 #   include "wx/msw/libraries.h"
 #endif
 
-#if (defined(__GNUC__) && __GNUC__ < 3)
-#define wxNEEDS_CHARPP
-#endif
-
 /*
     Note that wx/msw/gccpriv.h must be included after defining UNICODE and
     _UNICODE macros as it includes _mingw.h which relies on them being set.

include/wx/testing.h

@@ -503,11 +503,6 @@ private:
  */
 #ifdef HAVE_VARIADIC_MACROS
 
-// See wx/cpp.h for the explanations of this hack.
-#if defined(__GNUC__) && __GNUC__ == 3
-    #pragma GCC system_header
-#endif /* gcc-3.x */
-
 #define wxTEST_DIALOG(codeToRun, ...)                                          \
     {                                                                          \
         wxTEST_DIALOG_HOOK_CLASS wx_hook(__FILE__, __LINE__, __WXFUNCTION__);  \