If you don’t know what Clutch is then check this GitHub page. In short, it’s for extracting .ipa files from the installed apps.
You need to have a jailbroken iPhone to be able to install and use it.
When you download Clutch 2.0.4 from the official Release page you might encounter such an error
Error: Failed to dump <library> with arch arm64
I think it appears every time when the application has some external library, I tested 3 applications and 1 game and all applications have this problem but the game didn’t.
So, how to use it and remove errors?
You need to build a Clutch on your own.
Firstly, download code from the latest commit, I downloaded 77076318c2180cda335f83d6fb90f56cd82bcba2 commit, link.
Then open this project in the command line and build the project.
xcodebuild clean build
Now you have the Clutch file inside the build directory. Now you can try to copy it to the iPhone and use it.
However, there could be some errors related to signing profile. To resolve it, you need to open the project in Xcode and sign the app with your profile. Related to Tatsh’s answer you need to have a paid developer account. I didn’t test it with a normal account.
After changing the signing profile you can build (not run, because running will fail anyway) project and the new Clutch file will work. At least it worked in my case.
Now you need to copy (using SCP) Clutch file to your iPhone and the errors should disappear.
If you encounter a similar error and this solution won’t help you, let me know, maybe I’ll be able to help you with it 🙂