Adapt to new location of sysroot

Also stop passing -Wrust-2018-idioms as it doesn’t appear the new in-tree
Rust build support does so and it was just there to match.

Change-Id: Ie92d208db17218952d75aa56fe59bc891c9284ff
Reviewed-on: https://fuchsia-review.googlesource.com/c/fargo/+/377294
Reviewed-by: Erick Tryzelaar <etryzelaar@google.com>
diff --git a/src/lib.rs b/src/lib.rs
index 533663c..619ebd5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -362,7 +362,6 @@
         format!("-Clink-arg=-L{}", clang_resource_lib.to_string_lossy()),
         format!("-Clink-arg=--sysroot={}", sysroot_as_path.to_string_lossy()),
         format!("-Lnative={}", shared_libraries_path(target_options)?.to_string_lossy()),
-        "-Wrust-2018-idioms".to_string(),
     ];
 
     if get_triple_cpu(target_options) == "aarch64" {
diff --git a/src/sdk.rs b/src/sdk.rs
index b54ef32..141c156 100644
--- a/src/sdk.rs
+++ b/src/sdk.rs
@@ -119,12 +119,11 @@
 
 pub fn sysroot_path(options: &TargetOptions<'_, '_>) -> Result<PathBuf, Error> {
     Ok(target_out_dir(&options.config)?
-        .join("sdk")
-        .join("exported")
-        .join("zircon_sysroot")
-        .join("arch")
-        .join(&options.config.fuchsia_arch)
-        .join("sysroot"))
+        .join("x64-shared")
+        .join("gen")
+        .join("build")
+        .join("config")
+        .join("fuchsia"))
 }
 
 pub fn zircon_build_path(config: &FuchsiaConfig) -> Result<PathBuf, Error> {