BUG #5674: initdb failed if path contains symlink

The following bug has been logged online:

Bug reference:      5674
Logged by:          Itagaki Takahiro
Email address:      itagaki.takahiro@gmail.com
PostgreSQL version: 9.0.0 (32bit)
Operating system:   Windows 7 (64bit)
Description:        initdb failed if path contains symlink
Details:

Windows 7 supports symbolic links like UNIX,
but initdb cannot initialize a database cluster
if the path (-D) contains symlinks.

> mkdir D:\real
> mklink /D D:\link D:\real
> initdb -D D:\real\pgdata --encoding=UTF8 --locale=C
  => OK
> initdb -D D:\link\pgdata2 --encoding=UTF8 --locale=C
  => could not create directory "D:/link": File exists