Log Message:
update to 0.3.5
changes:
- Fix asn1_octet_der to handle writes of zero-length buffers, before
  it did not write the ASN.1 length for a zero-length buffer.  This caused
  ASN.1 encodings to be incorrect on 64-bit platforms.
- Add self test that attempt to trigger the above bug.
- Fix test of -Wno-pointer-sign.
- Improve cross-compilation to MinGW by using AC_LIBTOOL_WIN32_DLL.