Bug#1108401: ggml: blas, hip, vulkan backends do not meet llama.cpp's Depends

[Rongrong <i@rong.moe>]

Source: ggml
Version: 0.0~git20250618.9e4bee1-1
Severity: important

Dear Maintainer,

Since llama.cpp 5318+dfsg-2, libggml-{blas,hip,vulkan} do not meet the
former's Depends. The only installable backend is libggml-cpu.

This is probably because ggml backends only Provides unversioned
libggml-backend instead of a versioned one, while llama.cpp Depends on
the latter.

   $ sudo apt install llama.cpp libggml-vulkan
   libggml-vulkan is already the newest version (0.0~git20250618.9e4bee1-1).
   Solving dependencies... Error!
   Some packages could not be installed. This may mean that you have
   requested an impossible situation or if you are using the unstable
   distribution that some required packages have not yet been created
   or been moved out of Incoming.
   The following information may help to resolve the situation:
   
   Unsatisfied dependencies:
    libggml-cpu : Conflicts: libggml-backend
    libggml-vulkan : Conflicts: libggml-backend
   Error: Unable to correct problems, you have held broken packages.
   Error: The following information from --solver 3.0 may provide additional context:
      Unable to satisfy dependencies. Reached two conflicting decisions:
      1. libggml-cpu:amd64 is selected for install because:
         1. llama.cpp:amd64=5760+dfsg-1 is selected as an upgrade
         2. llama.cpp:amd64=5760+dfsg-1 Depends libggml-cpu (= 0.0~git20250618.9e4bee1-1) | libggml-backend (= 0.0~git20250618.9e4bee1-1)
      2. libggml-cpu:amd64 is not selected for install because:
         1. libggml-vulkan:amd64 is selected for install
         2. libggml-vulkan:amd64 is available in version 0.0~git20250618.9e4bee1-1
         3. libggml-cpu:amd64 Conflicts libggml-backend
            [selected libggml-vulkan:amd64=0.0~git20250618.9e4bee1-1]

Thanks,
Rong