Define ACO_AUTOAPPEND for MinGW/Cygwin.

Apparently this symbol is not defined in MinGW headers neither, so do it
ourselves as well.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67570 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/textentry.cpp

@@ -59,6 +59,10 @@
 #if defined(__MINGW32__) || defined (__WATCOMC__) || defined(__CYGWIN__)
     // needed for IID_IAutoComplete, IID_IAutoComplete2 and ACO_AUTOSUGGEST
     #include <shlguid.h>
+
+    #ifndef ACO_AUTOAPPEND
+        #define ACO_AUTOAPPEND 0x02
+    #endif
 #endif
 
 #ifndef ACO_UPDOWNKEYDROPSLIST