Index: minisat/utils/System.cc
--- minisat/utils/System.cc.orig
+++ minisat/utils/System.cc
@@ -71,13 +71,13 @@ double Minisat::memUsedPeak(bool strictlyPeak) { 
     double peak = memReadPeak() / (double)1024;
     return peak == 0 && !strictlyPeak ? memUsed() : peak; }
 
-#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__gnu_hurd__)
+#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__) || defined(__gnu_hurd__)
 
 double Minisat::memUsed() {
     struct rusage ru;
     getrusage(RUSAGE_SELF, &ru);
     return (double)ru.ru_maxrss / 1024; }
-double Minisat::memUsedPeak() { return memUsed(); }
+double Minisat::memUsedPeak(bool strictlyPeak) { return memUsed(); }
 
 
 #elif defined(__APPLE__)