BUILD/MEDIUM: threads: enable cpu_affinity on osx

Enable it but on a per thread basis only using Darwin native API.
diff --git a/Makefile b/Makefile
index 9cacb93..fd8edc5 100644
--- a/Makefile
+++ b/Makefile
@@ -356,7 +356,7 @@
 # Mac OS/X
 ifeq ($(TARGET),osx)
   set_target_defaults = $(call default_opts, \
-    USE_POLL USE_TPROXY USE_LIBCRYPT USE_THREAD USE_KQUEUE)
+    USE_POLL USE_TPROXY USE_LIBCRYPT USE_THREAD USE_CPU_AFFINITY USE_KQUEUE)
   EXPORT_SYMBOL  = -export_dynamic
 endif
 
diff --git a/src/haproxy.c b/src/haproxy.c
index db6f21f..a4f2e0d 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -59,6 +59,11 @@
 #endif
 #include <pthread_np.h>
 #endif
+#ifdef __APPLE__
+#include <mach/mach_types.h>
+#include <mach/thread_act.h>
+#include <mach/thread_policy.h>
+#endif
 #endif
 
 #if defined(USE_PRCTL)
@@ -3164,7 +3169,7 @@
 			}
 			ret = cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID, -1, sizeof(cpuset), &cpuset);
 		}
-#else
+#elif defined(__linux__)
 			sched_setaffinity(0, sizeof(unsigned long), (void *)&global.cpu_map.proc[proc]);
 #endif
 #endif
@@ -3377,6 +3382,17 @@
 
 			if (i < MAX_THREADS &&       /* only the first 32/64 threads may be pinned */
 			    global.cpu_map.thread[i]) {/* only do this if the thread has a THREAD map */
+#if defined(__APPLE__)
+				int j;
+				unsigned long cpu_map = global.cpu_map.thread[i];
+
+				while ((j = ffsl(cpu_map)) > 0) {
+					thread_affinity_policy_data_t cpu_set = { j - 1 };
+					thread_port_t mthread = pthread_mach_thread_np(ha_thread_info[i].pthread);
+					thread_policy_set(mthread, THREAD_AFFINITY_POLICY, (thread_policy_t)&cpu_set, 1);
+					cpu_map &= ~(1UL << (j - 1));
+				}
+#else
 #if defined(__FreeBSD__) || defined(__NetBSD__)
 				cpuset_t cpuset;
 #else
@@ -3393,6 +3409,7 @@
 				}
 				pthread_setaffinity_np(ha_thread_info[i].pthread,
 						       sizeof(cpuset), &cpuset);
+#endif
 			}
 		}
 #endif /* !USE_CPU_AFFINITY */