From e279707a001c8f95f8a2bc51c0d19bf35bfc79ab Mon Sep 17 00:00:00 2001
From: Wan-Teh Chang <wtc@google.com>
Date: Fri, 11 Nov 2022 14:08:33 -0800
Subject: [PATCH] Build aviftest_helpers for are_images_equal.cc

If are_images_equal.cc is built, enable CXX and build the
aviftest_helpers library.

Fix the build failure when -DAVIF_BUILD_APPS=ON -DAVIF_BUILD_TESTS=ON
-DAVIF_ENABLE_GTEST=OFF is passed to the cmake command.

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 5af7ea560..632ba7a71 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -39,15 +39,17 @@ foreach(AVIFYUV_MODE limited rgb) # Modes drift and premultiply take more than 2
     add_test(NAME avifyuv_${AVIFYUV_MODE} COMMAND avifyuv -m ${AVIFYUV_MODE})
 endforeach()
 
-################################################################################
-# GoogleTest
-
-if(AVIF_ENABLE_GTEST)
+if(AVIF_ENABLE_GTEST OR AVIF_BUILD_APPS)
     enable_language(CXX)
     set(CMAKE_CXX_STANDARD 11)
     add_library(aviftest_helpers OBJECT gtest/aviftest_helpers.cc)
     target_link_libraries(aviftest_helpers avif_apps)
+endif()
 
+################################################################################
+# GoogleTest
+
+if(AVIF_ENABLE_GTEST)
     if(AVIF_LOCAL_GTEST)
         set(GTEST_INCLUDE_DIRS ${CMAKE_SOURCE_DIR}/ext/googletest/googletest/include)
         set(GTEST_LIBRARIES