rust: Drop libgcc dependency

Rustc unstable option "link-native-libraries" is used to prevent the
linkage of other libraries via the #[link] directive. Add a dependency
to libclang_rt.builtins, similarly to cc.

Bug: 141331117
Test: lunch aosp_crosshatch-userdebug; m
Change-Id: I5c232291a5dd08a99e6a12a1295e30bb8e4fcaf1
diff --git a/rust/compiler.go b/rust/compiler.go
index 98ad7ad..200af90 100644
--- a/rust/compiler.go
+++ b/rust/compiler.go
@@ -281,7 +281,7 @@
 	return deps
 }
 
-func bionicDeps(deps Deps, static bool) Deps {
+func bionicDeps(ctx DepsContext, deps Deps, static bool) Deps {
 	bionicLibs := []string{}
 	bionicLibs = append(bionicLibs, "liblog")
 	bionicLibs = append(bionicLibs, "libc")
@@ -294,9 +294,9 @@
 		deps.SharedLibs = append(deps.SharedLibs, bionicLibs...)
 	}
 
-	//TODO(b/141331117) libstd requires libgcc on Android
-	deps.StaticLibs = append(deps.StaticLibs, "libgcc")
-
+	if libRuntimeBuiltins := config.BuiltinsRuntimeLibrary(ctx.toolchain()); libRuntimeBuiltins != "" {
+		deps.StaticLibs = append(deps.StaticLibs, libRuntimeBuiltins)
+	}
 	return deps
 }