Search LLVM_ROOT for llvm binaries

Author: xhochy

recipe/build_base.bat

@@ -1,6 +1,8 @@
 setlocal EnableDelayedExpansion
 echo on
 
+set LLVM_ROOT=%BUILD_PREFIX%\Library
+
 :: Compile python, extensions and external libraries
 if "%ARCH%"=="64" (
    set PLATFORM=x64

recipe/meta.yaml

@@ -76,6 +76,7 @@ source:
       - patches/0023-Brand-conda-forge.patch
 {% endif %}
       - patches/0024-Do-not-define-pid_t-as-it-might-conflict-with-the-ac.patch
+      - patches/0025-Search-LLVM_ROOT-for-llvm-binaries.patch
 
 build:
   number: {{ build_number }}

recipe/patches/0025-Search-LLVM_ROOT-for-llvm-binaries.patch

@@ -0,0 +1,25 @@
+From 90e02e1f70b1ba2f1035b88e14fa26be2f63f7a0 Mon Sep 17 00:00:00 2001
+From: "Uwe L. Korn" <uwe.korn@quantco.com>
+Date: Wed, 3 Sep 2025 13:32:24 +0200
+Subject: [PATCH 25/25] Search LLVM_ROOT for llvm binaries
+
+---
+ Tools/jit/_llvm.py | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/Tools/jit/_llvm.py b/Tools/jit/_llvm.py
+index 606f280..6694c52 100644
+--- a/Tools/jit/_llvm.py
++++ b/Tools/jit/_llvm.py
+@@ -66,6 +66,11 @@ async def _get_brew_llvm_prefix(*, echo: bool = False) -> str | None:
+ 
+ @_async_cache
+ async def _find_tool(tool: 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 await _check_tool_version(path, echo=echo):
++            return path
+     # Unversioned executables:
+     path = tool
+     if await _check_tool_version(path, echo=echo):