debootstrap_action: don't assume the host is amd64

This change marks the target architecture as "foreign" if it differs
from the current host architecture, instead of hardcoding an expected
host architecture.

Due to Debian architectures not translating directly to their Go
equivalents (like `mips*el` being `mips*le` instead, or `i386` being
simply `386` in Go), this will only work for `amd64`, `arm64` and
`riscv64` hosts. However, it seems unlikely running `debos` on a 32-bit
host (or even on `mips64el`) will become a compelling use-case in the
future, making this issue an acceptable limitation.

Signed-off-by: Arnaud Ferraris <[email protected]>

actions/debootstrap_action.go

@@ -56,6 +56,7 @@ import (
 	"os"
 	"path"
 	"strings"
+	"runtime"
 
 	"github.com/go-debos/debos"
 	"github.com/go-debos/fakemachine"
@@ -212,8 +213,8 @@ func (d *DebootstrapAction) Run(context *debos.DebosContext) error {
 		cmdline = append(cmdline, fmt.Sprintf("--components=%s", s))
 	}
 
-	/* FIXME drop the hardcoded amd64 assumption" */
-	foreign := context.Architecture != "amd64"
+	/* Only works for amd64, arm64 and riscv64 hosts, which should be enough */
+	foreign := context.Architecture != runtime.GOARCH
 
 	if foreign {
 		cmdline = append(cmdline, "--foreign")