use system cython on linux

Author: mattip

recipe/build-core.sh

@@ -30,8 +30,6 @@ build --host_platform=//bazel_toolchain:build_platform
 build --experimental_ui_max_stdouterr_bytes=16000000
 build --local_ram_resources=HOST_RAM*.8 --local_cpu_resources=2
 EOF
-else
-  echo "build --action_env=PYTHON_BIN_PATH=$PATH" >> .bazelrc 
 fi
 
 echo '---------------- .bazelrc --------------------------'

recipe/meta.yaml

@@ -11,6 +11,7 @@ source:
     - patches/0001-Disable-making-entry-scripts.patch
     - patches/0002-Ignore-warnings-in-event.cc-and-logging.cc.patch
     - patches/0003-remove-dependencies.patch
+    - patches/0010-use-system-cython-by-smlinking.patch  # [linux]
     # See https://github.com/conda-forge/ray-packages-feedstock/issues/136
     # Keep in sync with current or active migration of libgrpc to avoid
     # ABI breakage

recipe/patches/0010-use-system-cython-by-smlinking.patch

@@ -0,0 +1,34 @@
+From 3e80364b8ab6e1fd88c0cd5bc1183cfae84a71b8 Mon Sep 17 00:00:00 2001
+From: Matti Picus <matti.picus@gmail.com>
+Date: Thu, 31 Jul 2025 09:43:42 +1000
+Subject: [PATCH] use system cython by symlinking it into the bazel env
+
+---
+ bazel/cython.BUILD | 9 +++++++--
+ 1 file changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/bazel/cython.BUILD b/bazel/cython.BUILD
+index 220eea983f..4e5a5871ad 100644
+--- a/bazel/cython.BUILD
++++ b/bazel/cython.BUILD
+@@ -19,10 +19,15 @@ py_library(
+     visibility=["//visibility:public"],
+ )
+ 
++genrule(
++    name = "lncython",
++    outs = ["cython"],
++    cmd = "ln -s $$(which cython) $@",
++)
++
+ # May not be named "cython", since that conflicts with Cython/ on OSX
+ filegroup(
+     name="cython_binary",
+-    srcs=["cython.py"],
++    srcs=["cython"],
+     visibility=["//visibility:public"],
+-    data=["cython_lib"],
+ )
+-- 
+2.39.5 (Apple Git-154)
+