stub thread affinity stuff

Index: rts/System/Platform/Linux/CpuTopology.cpp
--- rts/System/Platform/Linux/CpuTopology.cpp.orig
+++ rts/System/Platform/Linux/CpuTopology.cpp
@@ -90,6 +90,9 @@ std::vector<int> get_online_cpus() {
 
 // Set CPU affinity to a specific core
 void set_cpu_affinity(uint32_t cpu) {
+#ifdef __OpenBSD__
+	return;
+#else
 	cpu_set_t mask;
 	CPU_ZERO(&mask);
 	CPU_SET(cpu, &mask);
@@ -98,6 +101,7 @@ void set_cpu_affinity(uint32_t cpu) {
 	if (pthread_setaffinity_np(thread, sizeof(mask), &mask) != 0) {
 		perror("pthread_setaffinity_np");
 	}
+#endif
 }
 
 // Detect Intel core type using CPUID 0x1A
