use argv[0] for executable

Index: rts/System/Main.cpp
--- rts/System/Main.cpp.orig
+++ rts/System/Main.cpp
@@ -98,6 +98,10 @@ int main(int argc, char* argv[])
 #undef MAX_ARGS
 #endif
 
+#ifdef __OpenBSD__
+	Platform::SetArgv0(argv[0]);
+#endif
+
 	return (Run(argc, argv));
 }
 
