From 739fe174a81467d80d6f2b89ef4e47f3e031704d Mon Sep 17 00:00:00 2001
From: Sutou Kouhei <kou@clear-code.com>
Date: Thu, 14 May 2026 09:29:26 +0900
Subject: [PATCH] GH-49974: [C++][CMake] Add missing result variable
 initialization

`find_package()`'s `VALIDATOR`'s result variable must be initialized
to `TRUE` by caller.
---
 cpp/cmake_modules/BuildUtils.cmake | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cpp/cmake_modules/BuildUtils.cmake b/cpp/cmake_modules/BuildUtils.cmake
index d9e06b1657bc..8556273a0d4c 100644
--- a/cpp/cmake_modules/BuildUtils.cmake
+++ b/cpp/cmake_modules/BuildUtils.cmake
@@ -117,6 +117,7 @@ function(arrow_create_merged_static_lib output_target)
     if(CMAKE_LIBTOOL)
       set(LIBTOOL_MACOS ${CMAKE_LIBTOOL})
       # Validate that CMAKE_LIBTOOL is Apple's libtool
+      set(is_apple_libtool TRUE)
       validate_apple_libtool(is_apple_libtool "${LIBTOOL_MACOS}")
       if(NOT is_apple_libtool)
         get_libtool_version("${LIBTOOL_MACOS}" _libtool_version_output)