internal/rosa: replace busybox dash with mksh

Toybox does not provide a shell, mksh fills that gap.

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

internal/rosa/busybox.go

@@ -338,7 +338,6 @@ cp busybox /system/bin/
 mkdir -pv /work/system/bin/
 busybox --install -s /work/system/bin/
 cp -v busybox /work/system/bin/
-ln -vs ../system/bin/hush /work/bin/sh
 mkdir -vp /work/usr/bin/
 ln -vs ../../system/bin/busybox /work/usr/bin/env
 `, pkg.Path(AbsUsrSrc.Append("busybox"), true, t.NewPatchedSource(

internal/rosa/gnu.go

@@ -59,6 +59,7 @@ func (t Toolchain) newAutoconf() pkg.Artifact {
 		t.Load(Make),
 		t.Load(M4),
 		t.Load(Perl),
+		t.Load(Bash),
 	}, nil, nil, `
 cd "$(mktemp -d)"
 /usr/src/autoconf/configure \
@@ -205,6 +206,7 @@ func (t Toolchain) newCoreutils() pkg.Artifact {
 	return t.New("coreutils-"+version, false, []pkg.Artifact{
 		t.Load(Make),
 		t.Load(Perl),
+		t.Load(Bash),
 
 		t.Load(KernelHeaders),
 	}, nil, nil, `
@@ -212,6 +214,8 @@ cd /usr/src/coreutils
 test_disable() { chmod +w "$2" && echo "$1" > "$2"; }
 
 test_disable '#!/bin/sh' gnulib-tests/test-c32ispunct.sh
+test_disable '#!/bin/sh' tests/split/line-bytes.sh
+test_disable '#!/bin/sh' tests/dd/no-allocate.sh
 
 cd "$(mktemp -d)"
 /usr/src/coreutils/configure \

internal/rosa/ninja.go

@@ -10,6 +10,7 @@ func (t Toolchain) newNinja() pkg.Artifact {
 	return t.New("ninja-"+version, false, []pkg.Artifact{
 		t.Load(CMake),
 		t.Load(Python),
+		t.Load(Bash),
 	}, nil, nil, `
 chmod -R +w /usr/src/ninja/
 mkdir -p /work/system/bin/ && cd /work/system/bin/

internal/rosa/rosa.go

@@ -189,14 +189,16 @@ func (t Toolchain) New(
 	const lcMessages = "LC_MESSAGES=C.UTF-8"
 
 	var (
-		path    = AbsSystem.Append("bin", "busybox")
-		args    = []string{"hush", absCureScript.String()}
+		path    = AbsSystem.Append("bin", "sh")
+		args    = []string{"mksh", absCureScript.String()}
 		support []pkg.Artifact
 	)
 	switch t {
 	case toolchainBusybox:
 		name += "-early"
 		support = slices.Concat([]pkg.Artifact{newBusyboxBin()}, extra)
+		path = AbsSystem.Append("bin", "busybox")
+		args[0] = "hush"
 		env = fixupEnviron(env, nil, "/system/bin")
 
 	case toolchainStage3:
@@ -252,6 +254,7 @@ ln -vs ../usr/bin /work/bin
 			compilerRT,
 			runtimes,
 			clang,
+			boot.Load(Mksh),
 			boot.Load(Busybox),
 		})
 		env = fixupEnviron(env, []string{