While we don't have C11's quick_exit() we do have timespec_get() and struct timespec/aligned_alloc().
Index: include/__config =================================================================== RCS file: /cvs/src/lib/libcxx/include/__config,v retrieving revision 1.6 diff -u -p -r1.6 __config --- include/__config 17 Jun 2019 22:28:51 -0000 1.6 +++ include/__config 7 Dec 2019 03:10:51 -0000 @@ -341,6 +341,9 @@ # if defined(__FreeBSD__) # define _LIBCPP_HAS_QUICK_EXIT # define _LIBCPP_HAS_C11_FEATURES +# elif defined(__OpenBSD__) +# define _LIBCPP_HAS_TIMESPEC_GET +# define _LIBCPP_HAS_C11_FEATURES # elif defined(__Fuchsia__) # define _LIBCPP_HAS_QUICK_EXIT # define _LIBCPP_HAS_TIMESPEC_GET
