add autoconf archive ax_count_cpus.m4 macro

git-svn-id: https://gnunet.org/svn/libmicrohttpd@32566 140774ce-b5e7-0310-ab8b-a85725594a96
Update m4/ax_count_cpus.m4 to support W32

git-svn-id: https://gnunet.org/svn/libmicrohttpd@32567 140774ce-b5e7-0310-ab8b-a85725594a96
Use number of CPUs in tests and examples

git-svn-id: https://gnunet.org/svn/libmicrohttpd@32568 140774ce-b5e7-0310-ab8b-a85725594a96