Remove checks for ancient gcc/MinGW versions.

Don't test for wxUSE_NORLANDER_HEADERS, this is always true since many, many
years.

Remove tests for gcc version < 3.3, notably 2.95: the minimal supported gcc
version is 3.4.

Closes #15727.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76549 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/textctrl.cpp

@@ -62,13 +62,7 @@
 #endif
 
 #if wxUSE_RICHEDIT
-
-// old mingw32 has richedit stuff directly in windows.h and doesn't have
-// richedit.h at all
-#if !defined(__GNUWIN32_OLD__) || defined(__CYGWIN10__)
     #include <richedit.h>
-#endif
-
 #endif // wxUSE_RICHEDIT
 
 #include "wx/msw/missing.h"