Eli Zaretskii <eliz@gnu.org> writes:

>> From: Alex Bochannek <alex@bochannek.com>
>> Date: Mon, 17 May 2021 20:53:41 -0700
>> 
>> There is no -e option for Windows FTP and ftp will terminate when
>> receiving an unknown option (tested version Windows 10.0.19042.928)
>> 
>> There is no -e option in Solaris FTP and I cannot test how it responds
>> to an unknown option.
>> 
>> I am proposing the below patch which resolves the problem on macOS with
>> GNU inetutils and does no harm for Netkit-ftp/lukemftp/tnftp.
>> 
>> However, because of the way a Windows client would respond, I am open to
>> different approaches including considering this an inetutils bug
>> instead.
>
> How about making the default value depend on the value of system-type?

You mean something like this?