FindThreads: avoid failing in AIX when using -D_XOPEN_SOURCE=500
A rebased solution to the proposed code from !7131 (closed) on top of recent improvements to the FindThreads module.
Tested on AIX 7.1, not to introduce any regressions and allow for the following (or its C equivalent) to work both with GNU and XL compilers (with and without THREADS_PREFER_PTHREAD_FLAG)
cmake_minimum_required(VERSION 3.22.0)
project(test CXX)
list(APPEND CMAKE_REQUIRED_DEFINITIONS "-D_XOPEN_SOURCE=500")
set(THREADS_PREFER_PTHREAD_FLAG true)
find_package(Threads REQUIRED)
message("DEBUG: INIT = ${CMAKE_THREAD_LIBS_INIT}")
Topic-rename: FindThreads-aix
Edited by Carlo Arenas