So I can install a private version of the Cygwin DLL without conflictng with the system cygwin?
Actually, if you are very careful, you can have two different versions of the Cygwin DLL installed on your system at the same time but they must be run serially. This means that you can’t be running programs using both versions of Cygwin at the same time. Please be aware that currently both versions will use the same mount table entries although this wil change in Cygwin version 1.7.x. This usage is not recommeded for novices. Only limited support will be provided in the mailing lists if you run into problems.