image: bring back the pre-PR#462 BootcDiskImage

[mvo5]

This commit brings back the pre-PR#462 version of BootcDiskImage as BootcLegacyDiskImage. The rational is that right now we cannot use bootc install to-filesystem for cross arch building the FITRIM ioctl is not supported by qemu-user

To fix this is requires any of the following:

1. ensure install: Add --skip-finalize containers/bootc#462 is available everywhere we care about
2. ensure https://www.mail-archive.com/qemu-devel@nongnu.org/msg1034508.html is available everywhere we care about
3. bind mount /usr/bin/true over /usr/bin/fsfreeze inside the buildroot. This bind mount can be done via org.osbuild.bind but it leaks into the manifest and that does not feel great.

So the alternative is to keep using the "old" pipeline that does not yet use bootc install to-filesystem to for cross-arch builds and the new pipeline for everything else. The selection will happen on the level of bib.

This is all not nice and fragile and needs to be removed/reverted again but short term might be the only thing we can do.

With that we can do in bib:

index 1692a03..eb3b1cb 100644
--- a/bib/cmd/bootc-image-builder/image.go
+++ b/bib/cmd/bootc-image-builder/image.go
@@ -126,7 +126,13 @@ func manifestForDiskImage(c *ManifestConfig, rng *rand.Rand) (*manifest.Manifest
        mf := manifest.New()
        mf.Distro = manifest.DISTRO_FEDORA
        runner := &runner.Linux{}
-       err = img.InstantiateManifestFromContainers(&mf, []container.SourceSpec{containerSource}, runner, rng)
+
+       if c.Architecture != arch.Current() {
+               legacyImg := image.NewBootcLegacyDiskImage(img)
+               err = legacyImg.InstantiateManifestFromContainers(&mf, []container.SourceSpec{containerSource}, runner, rng)
+       } else {
+               err = img.InstantiateManifestFromContainers(&mf, []container.SourceSpec{containerSource}, runner, rng)
+       }
 
        return &mf, err
 }

[ondrejbudai]

Thanks! :)