--- a/ipc/chromium/src/base/debug_util_posix.cc
+++ b/ipc/chromium/src/base/debug_util_posix.cc
@@ -15,16 +15,19 @@
 #include <sys/param.h>
 #include <sys/types.h>
 #include <unistd.h>
 #if MOZ_HAVE_EXECINFO_H
 #include <execinfo.h>
 #endif
 
 #if defined(OS_MACOSX) || defined(OS_BSD)
+#if defined(OS_OPENBSD)
+#include <sys/proc.h>
+#endif
 #include <sys/sysctl.h>
 #endif
 
 #if defined(OS_DRAGONFLY) || defined(OS_FREEBSD)
 #include <sys/user.h>
 #endif
 
 #include "base/basictypes.h"