cmake HAVE_THREADS_H examples

HDFGroup/hdf5 CMakeLists.txt :835 

elseif (HAVE_THREADS_H)

baresip/re cmake/re-config.cmake :81 

check_include_file(threads.h HAVE_THREADS_H)

awawa-dev/HyperHDR external/CMakeLists.txt :120 

check_include_file("threads.h" HAVE_THREADS_H)