Users may possibly use the CYGWIN variable to customize their CYGWIN installations. MSYS should not be affected by this. Example:
In a CMD shell, run:
> set CYGWIN=
Now, set the CYGWIN variable to tty:
> set CYGWIN=tty
Notice the absence of the ftp prompt.
^C (CONTROL+C) ignored when CYGWIN=tty set
If we really want to keep a variable for customizing MSYS, it should have another name, like MSYS_CONFIG. Also, we should review the options which are truly useful for MSYS.