--- hotspot/src/os_cpu/bsd_amd64/vm/os_bsd_amd64.cpp.orig	2010-11-09 00:00:38 +0100
+++ hotspot/src/os_cpu/bsd_amd64/vm/os_bsd_amd64.cpp	2010-11-09 00:17:00 +0100
@@ -31,7 +31,7 @@
 #include <poll.h>
 #include <inttypes.h>
 
-# ifdef __FreeBSD__
+# if defined(__FreeBSD__) || defined(__DragonFly__)
 #  define context_rip uc_mcontext.mc_rip
 #  define context_rsp uc_mcontext.mc_rsp
 #  define context_rax uc_mcontext.mc_rax