help with installing ext-ffi

[tacman]

Very cool package, thanks for releasing it. Locally, I can see a nice speedup using it over gd.

But I can't figure out how to deploy it to our production server, which is using dokku and the heroku buildpacks.

Installing platform packages...
remote: 
remote:  !     ERROR: Failed to install system packages!
remote:  !     
remote:  !     Your platform requirements (for runtimes and extensions) could
remote:  !     not be resolved to an installable set of dependencies, or a
remote:  !     platform package repository was unreachable.
remote:  !     
remote:  !     This usually means that you (or packages you are using) depend
remote:  !     on a combination of PHP versions and/or extensions that are
remote:  !     currently not available on Heroku.
remote:  !     
remote:  !     The following is the full output from the installation attempt:
remote:  !     
remote:  !     > Loading repositories with available runtimes and extensions
remote:  !     > Updating dependencies
remote:  !     > Your requirements could not be resolved to an installable set of packages.
remote:  !     > 
remote:  !     >   Problem 1
remote:  !     >     - composer.json/composer.lock requires ext-ffi * -> could not be found in any version, there may be a typo in the package name.
remote:  !     >   Problem 2
remote:  !     >     - Root composer.json requires jcupitt/vips v2.3.0 -> satisfiable by jcupitt/vips[v2.3.0].
remote:  !     >     - jcupitt/vips v2.3.0 requires ext-ffi * -> could not be found in any version, there may be a typo in the package name.
remote:  !     > 
remote:  !     
remote:  !     For reference, the following runtimes are currently available:
remote:  !     
remote:  !     PHP:  8.3.1, 8.3.0, 8.2.14, 8.2.13, 8.2.12, 8.2.11, 8.2.10, 
remote:  !     8.2.9, 8.2.8, 8.2.7, 8.2.6, 8.2.5, 8.2.4, 8.2.3, 8.2.2, 
remote:  !     8.2.1, 8.1.27, 8.1.26, 8.1.25, 8.1.24, 8.1.23, 8.1.22, 
remote:  !     8.1.21, 8.1.20, 8.1.19, 8.1.18, 8.1.17, 8.1.16, 8.1.15, 
remote:  !     8.1.14, 8.1.13, 8.1.12, 8.1.11, 8.1.10, 8.1.9, 8.1.8, 
remote:  !     8.1.7, 8.1.6

Any suggestions or alteratives?

Thanks.

[chregu]

It needs the FFI PHP extension installed and enabled. And also the vips libraries itself.
While FFI may be installed in Heroku Buildpacks (but not enabled?), the vips libraries are most certainly not (or would surprise me).
But I have not much of an idea about Heroku Buildpacks, unfortunately