internal/rosa/make: split build and check

Doing these together breaks far too many buggy makefiles.

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

internal/rosa/toybox.go

@@ -19,7 +19,7 @@ func (t Toolchain) newToybox(suffix, script string) pkg.Artifact {
 		SkipConfigure: true,
 
 		ScriptEarly: `
-LDFLAGS="${LDFLAGS} -static"
+LDFLAGS="${LDFLAGS:-''} -static"
 
 chmod +w /bin/
 ln -rs "$(which bash)" /bin/ || true
@@ -37,13 +37,14 @@ make defconfig
 sed -i \
 	's/^CONFIG_TOYBOX_ZHELP=y$/CONFIG_TOYBOX_ZHELP=0/' \
 	.config
-
-make "-j$(nproc)"
 `,
 		ScriptConfigured: script,
-		CheckName:        "USER=cure tests",
 		SkipCheck:        t.isStage0(),
-		ScriptInstall:    "PREFIX=/work/system/bin make install_flat",
+		Check: []string{
+			"USER=cure",
+			"tests",
+		},
+		ScriptInstall: "PREFIX=/work/system/bin make install_flat",
 		Script: `
 mkdir -p /work/usr/bin
 ln -s ../../system/bin/env /work/usr/bin