chore: use hermetic_llvm for macos execution

Simdutf has this check for enabling atomic operations:

```
  #if __cpp_lib_atomic_ref >= 201806L
    #define SIMDUTF_ATOMIC_REF 1
  #endif // __cpp_lib_atomic_ref
```

Which evidently fails on the runner's macos version, which spits out the following error:

```
external/v8/src/builtins/builtins-typed-array.cc:524:28: error: no member named 'atomic_base64_to_binary_safe' in namespace 'simdutf'; did you mean 'base64_to_binary_safe'?
  524 |     simd_result = simdutf::atomic_base64_to_binary_safe(
      |                   ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                            base64_to_binary_safe
external/simdutf/simdutf.h:4369:1: note: 'base64_to_binary_safe' declared here
 4369 | base64_to_binary_safe(const char *input, size_t length, char *output,
      | ^
external/v8/src/builtins/builtins-typed-array.cc:837:35: error: no member named 'atomic_binary_to_base64' in namespace 'simdutf'; did you mean 'binary_to_base64'?
  837 |       simd_result_size = simdutf::atomic_binary_to_base64(
      |                          ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
      |                                   binary_to_base64
external/simdutf/simdutf.h:4110:8: note: 'binary_to_base64' declared here
 4110 | size_t binary_to_base64(const char *input, size_t length, char *output,
      |        ^
external/v8/src/builtins/builtins-typed-array.cc:525:9: error: cannot initialize a parameter of type 'const char *' with an rvalue of type 'const char16_t *'

```

Signed-off-by: Matt Leon <[email protected]>

Author: leonm1

.bazelrc

@@ -67,7 +67,17 @@ build:gcc --action_env=BAZEL_COMPILER=gcc
 build:gcc --action_env=CC=gcc
 build:gcc --action_env=CXX=g++
 
+build:hermetic --incompatible_enable_cc_toolchain_resolution
+build:hermetic --action_env BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1
+build:hermetic --extra_toolchains @emsdk//emscripten_toolchain:cc-toolchain-wasm
+
 # Use vendored LLVM C/C++ compiler.
+build:hermetic-llvm --config=hermetic
+build:hermetic-llvm --extra_toolchains @llvm_toolchain//:cc-toolchain-x86_64-linux
+
+build:hermetic-llvm-macos-amd64 --config=hermetic
+build:hermetic-llvm-macos-amd64 --extra_toolchains @llvm_toolchain//:cc-toolchain-x86_64-darwin
+
 build:hermetic-llvm --incompatible_enable_cc_toolchain_resolution
 build:hermetic-llvm --action_env BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1
 build:hermetic-llvm --extra_toolchains @llvm_toolchain//:cc-toolchain-x86_64-linux
@@ -76,6 +86,7 @@ build:hermetic-llvm --extra_toolchains @emsdk//emscripten_toolchain:cc-toolchain
 
 # Use vendored LLVM C/C++ compiler (cross-compile to Linux/aarch64).
 build:linux-aarch64-cross --config=hermetic-llvm
+build:linux-aarch64-cross --extra_toolchains @llvm_aarch64//:cc-toolchain-aarch64-linux
 build:linux-aarch64-cross --platforms @toolchains_llvm//platforms:linux-aarch64
 build:linux-aarch64-cross --cxxopt --gcc-install-dir=external/sysroot_linux_arm64/usr/lib/gcc/aarch64-linux-gnu/13/
 build:linux-aarch64-cross --test_env=QEMU_LD_PREFIX=/usr/aarch64-linux-gnu/

.github/workflows/test.yml

@@ -181,6 +181,7 @@ jobs:
           os: macos-15
           arch: x86_64
           action: test
+          flags: --config=hermetic-llvm-macos-amd64
           cache: true
         - name: 'WAMR interp on Linux/x86_64'
           engine: 'wamr-interp'