diff --git a/src/common/strconv.cpp b/src/common/strconv.cpp
index c56719561e..dd1844c5b2 100644
--- a/src/common/strconv.cpp
+++ b/src/common/strconv.cpp
@@ -333,7 +333,7 @@ wxMBConv::FromWChar(char *dst, size_t dstLen,
             return wxCONV_FAILED;
 
         dstWritten += lenChunk;
-        if ( isNulTerminated )
+        if ( src+lenChunk < srcEnd || isNulTerminated )
             dstWritten += lenNul;
 
         if ( dst )
@@ -345,7 +345,7 @@ wxMBConv::FromWChar(char *dst, size_t dstLen,
                 return wxCONV_FAILED;
 
             dst += lenChunk;
-            if ( isNulTerminated )
+            if ( src+lenChunk < srcEnd || isNulTerminated )
                 dst += lenNul;
         }
     }
@@ -3371,6 +3371,8 @@ wxCharBuffer wxSafeConvertWX2MB(const wchar_t *ws)
 
 #ifdef __WINDOWS__
     WX_DEFINE_GLOBAL_CONV2(wxMBConv, wxMBConv_win32, wxConvLibc, wxEMPTY_PARAMETER_VALUE);
+#elif 0 // defined(__WXOSX__)
+    WX_DEFINE_GLOBAL_CONV2(wxMBConv, wxMBConv_cf, wxConvLibc,  (wxFONTENCODING_UTF8));
 #else
     WX_DEFINE_GLOBAL_CONV2(wxMBConv, wxMBConvLibc, wxConvLibc, wxEMPTY_PARAMETER_VALUE);
 #endif