If you can find a copy of an older Xcode DMG, then you can install it. The official downloads section on the Apple Developer site requires an account (basically an AppleID_. I believe you can make an account for free and only need to pay to distribute on the app store and run a build on a mobile device.

Alex, you most likely already have an AppleID. If so, try this link:  Downloads. Once logged in, click the small "More" link to the upper right. Then scroll down to find the latest Xcode 11.3 which I think is the last one supported by Mojave. We recently had to do this for my wife's work laptop as she had the same issue.

If the login does not work, you need to open/associate your AppleID with a developer account. I don't remember anything about this as I did it so long ago now.

Note: This is not a new issue and a little Google-fu would have turned up info like https://stackoverflow.com/questions/10335747/how-to-download-xcode-dmg-or-xip-file

On May 29, 2020, at 7:09 PM, pd-dev-request@lists.iem.at wrote:

Date: Fri, 29 May 2020 19:09:10 +0200
From: Christof Ressi <info@christofressi.com>
To: pd-dev <pd-dev@lists.iem.at>
Subject: Re: [PD-dev] [PD] Catalina makes Pd take too long to load
externals? + Other annoyances.
Message-ID: <388e5909-355e-34f8-97d3-2717b8f27568@christofressi.com>
Content-Type: text/plain; charset="windows-1252"; Format="flowed"

I think you don't even need a developer account. I somehow remember that 
I've manually installed Xcode on my OSX 10.11 machine (which I can't 
upgrade to newer OSX versions because it's too old). But I might be wrong...

On 29.05.2020 18:05, Dan Wilcox wrote:
If you have an Apple Developer account, you can download old versions 
of Xcode back to 3.0 or so. You have to login to the developer site 
and find the Downloads section.

On May 29, 2020, at 6:02 PM, Alexandre Torres Porres 
<porres@gmail.com <mailto:porres@gmail.com>> wrote:

I need XCode to compile Pd and my externals, I was forced to upgrade 
to Catalina... and I cried...

I might find a way to get a torrent from pirate bay maybe that allows 
me to install XCode in mojave? I dunno...

--------
Dan Wilcox
@danomatika <http://twitter.com/danomatika>
danomatika.com <http://danomatika.com>
robotcowboy.com <http://robotcowboy.com>



--------
Dan Wilcox
@danomatika
danomatika.com
robotcowboy.com