Move prefer_rlib from binary to base compiler.

Moves the prefer_rlib property out from being exclusively a binary
property to one thats part of the base compiler properties. This
provides a little more control over the libstd linkage in our libraries.
Specifically, this enables a usecase where rust_ffi_shared needs to link
against libstd statically rather than dynamically.

Bug: 175121262
Test: New Soong tests pass.
Change-Id: If68014c684a75ba70e9d7dacbb01c7d360dc25a1
diff --git a/rust/library.go b/rust/library.go
index 971588d..9d731e6 100644
--- a/rust/library.go
+++ b/rust/library.go
@@ -159,14 +159,6 @@
 	return library.MutatedProperties.VariantIsStatic
 }
 
-func (library *libraryDecorator) stdLinkage(ctx *depsContext) RustLinkage {
-	// libraries should only request the RlibLinkage when building a static FFI or when variant is StaticStd
-	if library.static() || library.MutatedProperties.VariantIsStaticStd {
-		return RlibLinkage
-	}
-	return DefaultLinkage
-}
-
 func (library *libraryDecorator) source() bool {
 	return library.MutatedProperties.VariantIsSource
 }
@@ -228,7 +220,9 @@
 }
 
 func (library *libraryDecorator) autoDep(ctx BaseModuleContext) autoDep {
-	if library.rlib() || library.static() {
+	if library.preferRlib() {
+		return rlibAutoDep
+	} else if library.rlib() || library.static() {
 		return rlibAutoDep
 	} else if library.dylib() || library.shared() {
 		return dylibAutoDep
@@ -237,6 +231,15 @@
 	}
 }
 
+func (library *libraryDecorator) stdLinkage(ctx *depsContext) RustLinkage {
+	if library.static() || library.MutatedProperties.VariantIsStaticStd {
+		return RlibLinkage
+	} else if library.baseCompiler.preferRlib() {
+		return RlibLinkage
+	}
+	return DefaultLinkage
+}
+
 var _ compiler = (*libraryDecorator)(nil)
 var _ libraryInterface = (*libraryDecorator)(nil)
 var _ exportedFlagsProducer = (*libraryDecorator)(nil)