Use the patchelf on the system by default if not running from the snap and if it fails instruct the user to use patchelf as a part or as a build-snaps entry. Given that when using as a part the user can choose to not use filters to remove the file from prime, we also make a copy of the file to patch (breaking any potential existing hard link with the other steps) to avoid the problem of trying to patch the patchelf primed file with the same patchelf binary file. Signed-off-by: Sergio Schvezov <sergio.schvezov@canonical.com> - [x] Have you followed the [guidelines for contributing](https://github.com/snapcore/snapcraft/blob/master/CONTRIBUTING.md)? - [x] Have you signed the [CLA](http://www.ubuntu.com/legal/contributors/)? - [x] If this is a bugfix. Have you checked that there is a bug report open for the issue you are trying to fix on [bug reports](https://bugs.launchpad.net/snapcraft)? - [x] If this is a new feature. Have you discussed the design on the [forum](https://forum.snapcraft.io)? - [x] Have you successfully run `./runtests.sh static`? - [x] Have you successfully run `./runtests.sh unit`? -----