Log Message:
Update to 2.1:

Version 2.1 (released 2009-04-17)
- Fix compilation failure on platforms that can't generate empty archives,
  e.g., Mac OS X.  Reported by David Reiser <dbreiser@gmail.com>.

Version 2.0 (released 2009-04-13)
- Optimized tree generation.
- ASN1 parser code re-generated using Bison 2.4.1.
- Build with more warning flags.  Many compiler warnings fixed.
- Compiled with -fvisibility=hidden by default if supported.
  See http://gcc.gnu.org/wiki/Visibility
- The libtasn1-config tool has been removed.
  For application developers, please stop using libtasn1-config for
  finding libtasn1, use proper autoconf checks or pkg-config instead.
  For users that need a libtasn1 that provides a libtasn1-config
  script (for use with older applications), use libtasn1 v1.x instead.
  Version 1.x is still supported.