cmake/tuklib_large_file_support.cmake: Add a missing include

v5.2 didn't build with CMake. Other branches had
include(CMakePushCheckState) in top-level CMakeLists.txt
which made the build work.

Fixes: 597f49b61475438a43a417236989b2acc968a686
(cherry picked from commit be4bf94446b6286a5dffdde85fc1d21448f4edff)
diff --git a/cmake/tuklib_large_file_support.cmake b/cmake/tuklib_large_file_support.cmake
index 0800faa..1079326 100644
--- a/cmake/tuklib_large_file_support.cmake
+++ b/cmake/tuklib_large_file_support.cmake
@@ -13,6 +13,7 @@
 #
 
 include("${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake")
+include(CMakePushCheckState)
 include(CheckCSourceCompiles)
 
 function(tuklib_large_file_support TARGET_OR_ALL)