Makefile: auto-detect btrfs headers for portable local builds

[HarshwardhanPatil07]

• make build-bink fails on systems without btrfs-progs-devel
• Add hack/btrfs_installed_tag.sh — probes for btrfs/ioctl.h and emits exclude_graphdriver_btrfs when headers are absent (same pattern used by Podman, Buildah, and Skopeo)
• On systems with btrfs-progs-devel installed, behavior is unchanged — btrfs compiles normally

harshpat@harshpat-thinkpadp1gen4i:~/Downloads/repos/bink$ make build-bink
=== Building bink CLI binary ===
go build -ldflags "-X github.com/bootc-dev/bink/internal/version.Version=dev -X github.com/bootc-dev/bink/internal/version.GitCommit=d30220c -X github.com/bootc-dev/bink/internal/version.BuildDate=2026-06-22T11:30:14Z" -o bink ./cmd/bink
# github.com/containers/storage/drivers/btrfs
../../../coderepo/pkg/mod/github.com/containers/storage@v1.58.0/drivers/btrfs/version.go:6:10: fatal error: btrfs/version.h: No such file or directory
    6 | #include <btrfs/version.h>
      |          ^~~~~~~~~~~~~~~~~
compilation terminated.
make: *** [Makefile:32: build-bink] Error 1

[alicefr]

@HarshwardhanPatil07 thanks for the PR! Looks good!

[jlebon]

Nice find. That requirement bothered me as well and I hadn't had time to investigate it properly.

Honestly, I think we should just always pass this tag. There's no reason we need whatever btrfs-specific features in that stack since everything is done through podman remote anyway.

[cgwalters]

I would suggest trying not to vendor the podman sources at all because that puts one on a huge CVE train - try to use e.g. github.com/docker/docker/client ?