Use LLVM_TOOLS_INSTALL_DIR to search for LLVM tools

Author: xhochy

Misc/NEWS.d/next/Build/2025-09-03-14-55-59.gh-issue-138451.-Qzh2S.rst

@@ -1 +1 @@
-Search for LLVM tools in ``LLVM_ROOT`` during the build.
+Search for LLVM tools in ``LLVM_TOOLS_INSTALL_DIR`` during the build.

Tools/jit/_llvm.py

@@ -73,8 +73,8 @@ async def _get_brew_llvm_prefix(llvm_version: str, *, echo: bool = False) -> str
 @_async_cache
 async def _find_tool(tool: str, llvm_version: str, *, echo: bool = False) -> str | None:
     # Explicitly defined LLVM installation location
-    if (llvm_root := os.getenv("LLVM_ROOT")) is not None:
-        path = os.path.join(llvm_root, "bin", tool)
+    if (llvm_tools_dir := os.getenv("LLVM_TOOLS_INSTALL_DIR")) is not None:
+        path = os.path.join(llvm_tools_dir, tool)
         if await _check_tool_version(path, llvm_version, echo=echo):
             return path
     # Unversioned executables: