Index: /trunk/src/VBox/ExtPacks/VBoxDTrace/Makefile.kmk
===================================================================
--- /trunk/src/VBox/ExtPacks/VBoxDTrace/Makefile.kmk	(revision 53987)
+++ /trunk/src/VBox/ExtPacks/VBoxDTrace/Makefile.kmk	(revision 53988)
@@ -99,4 +99,5 @@
  VBoxDTraceCmd_DEFS = RTMEM_WRAP_TO_EF_APIS
  #VBoxDTraceCmd_DEFS += YYDEBUG
+ VBoxDTraceCmd_DEFS.linux = _XOPEN_SOURCE=700
  VBoxDTraceCmd_SDKS = VBOX_ZLIB
  ifn1of ($(KBUILD_TARGET), win)