Fix the size of the buffer passed to wxTmemcpy() in wxTextDataObject.

This corrects fatal bug introduced in r72259: we must not multiply the string
length by sizeof(wxChar) as wxTmemcpy() does this internally.

See #14444.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72260 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/dobjcmn.cpp

@@ -425,8 +425,8 @@ bool wxTextDataObject::GetDataHere(void *buf) const
     // NOTE: use wxTmemcpy() instead of wxStrncpy() to allow
     //       retrieval of strings with embedded NULLs
     wxTmemcpy(static_cast<wxChar*>(buf),
-              textNative.c_str(),
-              (textNative.length() + 1)*sizeof(wxChar));
+              textNative.t_str(),
+              textNative.length() + 1);
 
     return true;
 }