internal/rosa: configurable architecture

This enables curing via binfmt.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/gnu.go

@@ -1,7 +1,6 @@
 package rosa
 
 import (
-	"runtime"
 	"slices"
 	"strconv"
 	"strings"
@@ -843,7 +842,7 @@ func (t Toolchain) newGnuTLS() (pkg.Artifact, string) {
 	)
 
 	var configureExtra []KV
-	switch runtime.GOARCH {
+	switch arch {
 	case "arm64":
 		configureExtra = []KV{
 			{"disable-hardware-acceleration"},
@@ -1148,7 +1147,7 @@ func (t Toolchain) newGCC() (pkg.Artifact, string) {
 	)
 
 	var configureExtra []KV
-	switch runtime.GOARCH {
+	switch arch {
 	case "amd64", "arm64":
 		configureExtra = append(configureExtra, KV{"with-multilib-list", "''"})
 	}