$OpenBSD: patch-libcilkrts_runtime_os-unix_c,v 1.1.1.1 2016/09/04 16:20:18 pascal Exp $
--- libcilkrts/runtime/os-unix.c.orig	Wed May 21 13:08:58 2014
+++ libcilkrts/runtime/os-unix.c	Tue Aug 23 16:19:52 2016
@@ -58,6 +58,8 @@
 // No additional include files
 #elif defined  __FreeBSD__
 // No additional include files
+#elif defined  __OpenBSD__
+// No additional include files
 #elif defined __CYGWIN__
 // Cygwin on Windows - no additional include files
 #elif defined  __VXWORKS__
@@ -376,7 +378,8 @@ COMMON_SYSDEP int __cilkrts_hardware_cpu_count(void)
     assert((unsigned)count == count);
 
     return count;
-#elif defined  __FreeBSD__ || defined __CYGWIN__ || defined __DragonFly__
+#elif defined  __FreeBSD__ || defined __CYGWIN__ || defined __DragonFly__ || \
+	defined __OpenBSD__
     int ncores = sysconf(_SC_NPROCESSORS_ONLN);
 
     return ncores;
