001-accept-llvm-20.1.patch

--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -160,6 +160,7 @@
 set(BUILD_SUPPORT_DIR "${CMAKE_SOURCE_DIR}/build-support")
 
 set(ARROW_LLVM_VERSIONS
+    "20.1"
     "19.1"
     "18.1"
     "17.0"