pinweaver/ti50: workaround to build with Clang-15 in Ti50 SDK

LIBCLANG_PATH cause weird issues that types from stdint.h not found:
  pinweaver_types.h:100:2: error: unknown type name 'uint8_t'
  pinweaver_types.h:105:2: error: unknown type name 'uint8_t'
  pinweaver_types.h:110:2: error: unknown type name 'uint8_t'
  ...

Commenting out LIBCLANG_PATH helps, but in general this is not a correct
behavior. Updating bindgen to 0.62 also didn't make a difference.

BUG=b:259282140
TEST=make, manually check that RISC-V target is correctly handled

Cq-Depend: chrome-internal:5146615
Change-Id: I9778afa3fb0f6c134e9f599f0bdb594ab6f36aea
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/pinweaver/+/4049022
Reviewed-by: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Owners-Override: Brad McKee <bradmckee@google.com>
Reviewed-by: Alyssa Haroldsen <kupiakos@google.com>
Auto-Submit: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Commit-Queue: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Tested-by: Vadim Sukhomlinov <sukhomlinov@chromium.org>
diff --git a/eal/ti50/build.rs b/eal/ti50/build.rs
index 0b67b6c..c5a901c 100644
--- a/eal/ti50/build.rs
+++ b/eal/ti50/build.rs
@@ -1,4 +1,4 @@
-// Copyright 2022 The ChromiumOS Authors.
+// Copyright 2022 The ChromiumOS Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -33,9 +33,10 @@
         .clang_arg("-DBIOMETRICS_DEV=false");
 
     if let Ok(sysroot) = env::var("RV_CLANG") {
+        // TODO(b/260111841, kupiakos): investigate turning LIBCLANG_PATH
+        // back on once Rust llvm updated.
         // Tell clang-sys to use our libclang that knows about RISC-V.
-        env::set_var("LIBCLANG_PATH", format!("{sysroot}/lib"));
-
+        // env::set_var("LIBCLANG_PATH", format!("{sysroot}/lib"));
         builder = builder
             // Needed for `#include <stdint.h>` to work.
             .clang_arg(format!("--sysroot={sysroot}"))