Implement rust_aconfig_library

rust_aconfig_library generates src/lib.rs and uses it to build library variants (dylib, rlib-rlib_std, and rlib-dylib_std) as of what `rust_library` produces

Test: go test
Change-Id: I6c4603691d4306c463c2e9521f5c11c30765b1e3

aconfig/init.go

@@ -16,6 +16,7 @@ package aconfig
 
 import (
 	"android/soong/android"
+
 	"github.com/google/blueprint"
 )
 
@@ -70,6 +71,20 @@ var (
 			},
 		}, "gendir")
 
+	rustRule = pctx.AndroidStaticRule("rust_aconfig_library",
+		blueprint.RuleParams{
+			Command: `rm -rf ${gendir}` +
+				` && mkdir -p ${gendir}` +
+				` && ${aconfig} create-rust-lib` +
+				`    --mode ${mode}` +
+				`    --cache ${in}` +
+				`    --out ${gendir}`,
+			CommandDeps: []string{
+				"$aconfig",
+				"$soong_zip",
+			},
+		}, "gendir", "mode")
+
 	// For all_aconfig_declarations
 	allDeclarationsRule = pctx.AndroidStaticRule("all_aconfig_declarations_dump",
 		blueprint.RuleParams{
@@ -92,5 +107,6 @@ func registerBuildComponents(ctx android.RegistrationContext) {
 	ctx.RegisterModuleType("aconfig_value_set", ValueSetFactory)
 	ctx.RegisterModuleType("cc_aconfig_library", CcAconfigLibraryFactory)
 	ctx.RegisterModuleType("java_aconfig_library", JavaDeclarationsLibraryFactory)
+	ctx.RegisterModuleType("rust_aconfig_library", RustAconfigLibraryFactory)
 	ctx.RegisterParallelSingletonType("all_aconfig_declarations", AllAconfigDeclarationsFactory)
 }