internal/rosa/llvm: early-runtimes for gentoo stage only

This bootstrap step is not required for a native Rosa OS stage0 distribution.

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

internal/rosa/llvm.go

@@ -64,7 +64,7 @@ func init() {
 		meta.Version = _meta.Version
 
 		early := _muslHeaders
-		if t.stage.isStage0() {
+		if t.stage.isStage0() && !t.stage.isRosa() {
 			// The LLVM build system uses the system installation when building with
 			// LLVM_LINK_LLVM_DYLIB, since it builds runtimes after the fact, using
 			// the just-built toolchain. This is unacceptable in stage0 due to the

internal/rosa/llvm_test.go

@@ -8,7 +8,7 @@ import (
 )
 
 func TestLLVMInputs(t *testing.T) {
-	const wantInputCount = 470
+	const wantInputCount = 466
 
 	_, llvm := rosa.MustLoad(rosa.H("llvm"))
 	var n int

internal/rosa/rosa.go

@@ -129,6 +129,11 @@ const (
 	_stageEnd
 )
 
+// isRosa returns whether t is derived from a Rosa OS stage0.
+func (t Stage) isRosa() bool {
+	return t >= stageEarly
+}
+
 // isStage0 returns whether t is a stage0 toolchain.
 func (t Stage) isStage0() bool {
 	switch t {