The directory contains:

	windows-flex-2.5.35.zip 
     cygwin-1.7.5-1-src.tar.bz2 

The windows-flex-2.5.35.zip file contains binaries for flex that can be used 
in Windows builds of Postgres, including those later than 8.4, which require 
a more modern version of flex than is usually available on Windows.

The cygwin-1.7.5-1-src.tar.bz2 contains source code for the cygwin1.dll that
is contained in the zip file. To build Postgres, you only need to download the
windows-flex-2.5.35.zip file.

To run this version of flex, you will need to set the M4 environment variable
to point to your installation of m4. You need one of these in order to run
both bison and flex, and it sometimes comes packaged with bison.

If you are using this in a buildfarm member, you can set that environment
variable in its config file, in the build_env stanza, something like:

	M4 => 'c:\path\to\bin\m4.exe',