Add support for using native spell checking in wxTextCtrl

Add wxTextCtrl::EnableSpellCheck() and implement it for wxMSW and
wxGTK3.

Closes #17544.

setup.h.in

@@ -216,6 +216,12 @@
 
 #define wxUSE_SECRETSTORE   0
 
+#if (defined(__WXGTK3__) || defined(__WXMSW__))
+#define wxUSE_SPELLCHECK 0
+#else
+#define wxUSE_SPELLCHECK 0
+#endif
+
 #define wxUSE_STDPATHS      0
 
 #define wxUSE_TEXTBUFFER    0