rust: Alias rust_ffi_rlib to rust_library_rlib

With the new transition mutators, the distinctions between rust_ffi_rlib
and rust_library_rlib are not necessary. This CL removes the remaining
distinctions to allow an unusual use case where a rust_library and a
rust_ffi_rlib would otherwise be created from the same source. This
would allow defining a single rust_library_rlib that works for both rust
modules and cc modules.

One key change is that rust_ffi_rlibs only produced an rlib-std variant
previously, and now produce dylib-std variants as well.This surfaced an
issue where a libstd linkage mismatch would cause rustc to throw a
consufing missing crate error. We instead add logic to catch this in
Soong and provide a more useful error message.

Bug: 383552450
Test: m rust
Test: m blueprint_tests
Change-Id: I611ca46934059735d06229952cfd8e0ab7050486
diff --git a/rust/compiler.go b/rust/compiler.go
index fd86917..b93019b 100644
--- a/rust/compiler.go
+++ b/rust/compiler.go
@@ -30,9 +30,8 @@
 type RustLinkage int
 
 const (
-	DefaultLinkage RustLinkage = iota
+	DylibLinkage RustLinkage = iota
 	RlibLinkage
-	DylibLinkage
 )
 
 type compiler interface {
@@ -69,7 +68,7 @@
 	Disabled() bool
 	SetDisabled()
 
-	stdLinkage(ctx *depsContext) RustLinkage
+	stdLinkage(device bool) RustLinkage
 	noStdlibs() bool
 
 	unstrippedOutputFilePath() android.Path
@@ -316,11 +315,11 @@
 	return aliases
 }
 
-func (compiler *baseCompiler) stdLinkage(ctx *depsContext) RustLinkage {
+func (compiler *baseCompiler) stdLinkage(device bool) RustLinkage {
 	// For devices, we always link stdlibs in as dylibs by default.
 	if compiler.preferRlib() {
 		return RlibLinkage
-	} else if ctx.Device() {
+	} else if device {
 		return DylibLinkage
 	} else {
 		return RlibLinkage