This is a duplicate of information present in readme.txt.  If you already
installed the older 20.0 release, this document explains how to upgrade.

------------------------

Upgrading to B20.1

If you downloaded the original B20.0 release, you should definitely at
least upgrade the Cygwin library to the version present in B20.1.  To do
this, download the file
@file{ftp://go.cygnus.com/pub/sourceware.cygnus.com/cygwin/cygwin-b20/cygwin1-20.1.dll.bz2},
decompress it with bunzip2, and then install the dll, replacing
the file cygwin-b20/H-i586-cygwin32/bin/cygwin1.dll in your original
installation of 20.0.

There are some additional patches in a few of the other tools
(including a gcc change that makes -mno-cygwin find the correct header
files).  In addition, the tools have been built with a compiled-in path
of /cygnus/cygwin-b20/ which will make some tools such as bison find
their library files without help from environment variables.
To install the full 20.1 release, you will need to download the
correct installer from scratch.  It will offer to uninstall the existing
release and replace it with 20.1 (You should choose to uninstall b20 and
proceed).

We have diff files on the ftp site that can be used to upgrade the
original B20.0 sources.  20.0-20.1-dev-src.diff.bz2 upgrades the
development tools sources.  20.0-20.1-user-src.diff.bz2 upgrades the
user tools sources.  They come compressed so you'll need to bunzip2 them
before proceeding.  As an example, if the development tools are in the
directory called "src" and the patch is in the directory above it, apply
the patch as follows:

cd src
patch -p1 -E < ../20.0-20.1-dev-src.diff