From: Zach Toogood <zach@yousician.com>
Subject: Fix CMake Threads dependency issue
Origin: upstream, https://github.com/abseil/abseil-cpp/commit/68494aae959dfbbf781cdf03a988d2f5fc7e4802
Bug: https://github.com/abseil/abseil-cpp/issues/668
Bug-Debian: https://bugs.debian.org/970333

Improve CMake support by finding the Threads module with find_dependency
rather than trying to include it directly. This silences a CMake warning.

--- a/CMake/abslConfig.cmake.in
+++ b/CMake/abslConfig.cmake.in
@@ -1,6 +1,7 @@
 # absl CMake configuration file.
 
-include(FindThreads)
+include(CMakeFindDependencyMacro)
+find_dependency(Threads)
 
 @PACKAGE_INIT@