diff -Naur libobjc2-2.1.orig/CMakeLists.txt libobjc2-2.1/CMakeLists.txt
--- libobjc2-2.1.orig/CMakeLists.txt	2020-08-23 17:10:20.000000000 +0200
+++ libobjc2-2.1/CMakeLists.txt	2020-09-03 10:51:38.716078009 +0200
@@ -344,7 +344,7 @@
 # threading implementation (we do for everything except thread-local storage)
 set(CMAKE_THREAD_PREFER_PTHREAD)
 include(FindThreads)
-set(objc_LINK_FLAGS "${objc_LINK_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
+target_link_libraries(objc Threads::Threads)