internal/rosa: create metadata alongside artifact

This enables deferring evaluation of azalea-based packages and fixes the longstanding quirk of version being disjoint from other metadata.

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

internal/rosa/ninja.go

@@ -7,8 +7,8 @@ func (t Toolchain) newNinja() (pkg.Artifact, string) {
 		version  = "1.13.2"
 		checksum = "ygKWMa0YV2lWKiFro5hnL-vcKbc_-RACZuPu0Io8qDvgQlZ0dxv7hPNSFkt4214v"
 	)
-	python, _ := t.Load(Python)
-	bash, _ := t.Load(Bash)
+	_, python := t.Load(Python)
+	_, bash := t.Load(Bash)
 	return t.New("ninja-"+version, 0, []pkg.Artifact{
 		python,
 		bash,
@@ -39,9 +39,7 @@ cp ninja /work/system/bin/
 	))), version
 }
 func init() {
-	native.MustRegister(&Artifact{
-		f: Toolchain.newNinja,
-
+	native.mustRegister(Toolchain.newNinja, &Metadata{
 		Name:        "ninja",
 		Description: "a small build system with a focus on speed",
 		Website:     "https://ninja-build.org/",