diff --git a/include/wx/filefn.h b/include/wx/filefn.h
index 3a3cc99a43..5cdc93b404 100644
--- a/include/wx/filefn.h
+++ b/include/wx/filefn.h
@@ -309,6 +309,15 @@ enum wxFileKind
         #endif
     #endif
 
+    #if wxHAS_HUGE_FILES
+        // wxFile is present and supports large files. Currently wxFFile
+        // doesn't have large file support with any Windows compiler (even
+        // Win64 ones).
+        #if wxUSE_FILE
+            #define WXFILE_LARGEFILE 1
+        #endif
+    #endif
+        
     // It's a private define, undefine it so nobody gets tempted to use it
     #undef wxHAS_HUGE_FILES
 #else // Unix platforms using configure
@@ -317,6 +326,14 @@ enum wxFileKind
         #define wxFileOffsetFmtSpec wxLongLongFmtSpec
         wxCOMPILE_TIME_ASSERT( sizeof(off_t) == sizeof(wxLongLong_t),
                                 BadFileSizeType );
+        // wxFile is present and supports large files
+        #ifdef wxUSE_FILE
+            #define WXFILE_LARGEFILE
+        #endif
+        // wxFFile is present and supports large files
+        #if SIZEOF_LONG == 8 || defined HAVE_FSEEKO
+            #define WXFFILE_LARGEFILE
+        #endif
     #else
         #define wxFileOffsetFmtSpec _T("")
     #endif
@@ -355,6 +372,12 @@ enum wxFileKind
     #define wxHAVE_NATIVE_LSTAT
 #endif // platforms
 
+#ifdef O_BINARY
+    #define wxO_BINARY O_BINARY
+#else
+    #define wxO_BINARY 0
+#endif
+
 // if the platform doesn't have symlinks, define wxLstat to be the same as
 // wxStat to avoid #ifdefs in the code using it
 #ifndef wxHAVE_NATIVE_LSTAT