The `_POSIX_TIMERS` macro is defined to -1, indicating no support for the POSIX timers option. This option indicates support for the `clock_getres`, `clock_gettime`, `clock_settime`, `nanosleep`, and `timer_*` functions. While the `timer_*` functions do not appear to be supported by OpenBSD, the ubiquitous `clock_*` functions are, and their man pages indicate that they conform to IEEE Std 1003.1-2008 POSIX.1.
Defining the `_POSIX_TIMERS` macro to -1 is problematic because conforming POSIX programs cannot use the `clock_*` functions in any capacity given that they may not be defined. It should not be defined to 1, however, because not all of the functions included in the timers option are supported by OpenBSD. Thus I suggest that the `_POSIX_TIMERS` macro is defined to 0, indicating conditional support, and that the unsupported functions be implemented with stubs as suggested by POSIX. It is worth noting that the timers option was moved to the base standard in POSIX-2008, meaning that all implementations conforming to the latest version of the POSIX standard must implement all interfaces included with it. In theory a program could check if the `_POSIX_VERSION` macro is defined with a value >= 200809, which OpenBSD does by default. This seems unreasonable since clearly, this is not accurate either. Similarly, the `_POSIX_MONOTONIC_CLOCK`, `_POSIX_CPUTIME`, and `_POSIX_THREAD_CPUTIME` macros are all defined with values >= 1, even though they imply `_POSIX_TIMERS` is >= 1 as well. The `_POSIX_CLOCK_SELECTION` macro is also defined as -1, however both the `pthread_condattr_getclock` and `pthread_condattr_setclock` functions are supported while the additional `clock_nanosleep` function is not.
