diff --git a/tools/Makefile b/tools/Makefile
index 3d3fd603e5..cb8652c796 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -194,7 +194,7 @@ qemu-traditional-recurse = \
 subdir-all-qemu-xen-traditional-dir: qemu-xen-traditional-dir-find
 	$(call qemu-traditional-recurse,\
 		$(QEMU_ROOT)/xen-setup \
-		--extra-cflags="$(EXTRA_CFLAGS_QEMU_TRADITIONAL)" \
+		--extra-cflags="-D__XEN_TOOLS__ $(EXTRA_CFLAGS_QEMU_TRADITIONAL)" \
 		$(IOEMU_EXTRA_LDFLAGS) \
 		--cpu=$(IOEMU_CPU_ARCH) \
 		$(IOEMU_CONFIGURE_CROSS); \
diff --git a/tools/Rules.mk b/tools/Rules.mk
index d47fa45198..9ef0b478f1 100644
--- a/tools/Rules.mk
+++ b/tools/Rules.mk
@@ -108,7 +108,9 @@ CFLAGS_libxenforeignmemory = -I$(XEN_LIBXENFOREIGNMEMORY)/include $(CFLAGS_xenin
 LDLIBS_libxenforeignmemory = $(XEN_LIBXENFOREIGNMEMORY)/libxenforeignmemory$(libextension)
 SHLIB_libxenforeignmemory  = -Wl,-rpath-link=$(XEN_LIBXENFOREIGNMEMORY)
 
-CFLAGS_libxenctrl = -I$(XEN_LIBXC)/include $(CFLAGS_libxentoollog) $(CFLAGS_libxenforeignmemory) $(CFLAGS_xeninclude)
+# code which compiles against libxenctrl get __XEN_TOOLS__ and
+# therefore sees the unstable hypercall interfaces.
+CFLAGS_libxenctrl = -I$(XEN_LIBXC)/include $(CFLAGS_libxentoollog) $(CFLAGS_libxenforeignmemory) $(CFLAGS_xeninclude) -D__XEN_TOOLS__
 SHDEPS_libxenctrl = $(SHLIB_libxentoollog) $(SHLIB_libxenevtchn) $(SHLIB_libxengnttab) $(SHLIB_libxengntshr) $(SHLIB_libxencall) $(SHLIB_libxenforeignmemory)
 LDLIBS_libxenctrl = $(SHDEPS_libxenctrl) $(XEN_LIBXC)/libxenctrl$(libextension)
 SHLIB_libxenctrl  = $(SHDEPS_libxenctrl) -Wl,-rpath-link=$(XEN_LIBXC)
@@ -159,7 +161,7 @@ SHDEPS_libxenlight = $(SHLIB_libxenctrl) $(SHLIB_libxenstore) $(SHLIB_libblktapc
 LDLIBS_libxenlight = $(SHDEPS_libxenlight) $(XEN_XENLIGHT)/libxenlight$(libextension)
 SHLIB_libxenlight  = $(SHDEPS_libxenlight) -Wl,-rpath-link=$(XEN_XENLIGHT)
 
-CFLAGS += -D__XEN_TOOLS__
+CFLAGS += -D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__
 
 # Get gcc to generate the dependencies for us.
 CFLAGS += -MMD -MF .$(if $(filter-out .,$(@D)),$(subst /,@,$(@D))@)$(@F).d
diff --git a/tools/debugger/gdbsx/xg/Makefile b/tools/debugger/gdbsx/xg/Makefile
index 78b4021ce9..6a8937b8f9 100644
--- a/tools/debugger/gdbsx/xg/Makefile
+++ b/tools/debugger/gdbsx/xg/Makefile
@@ -4,6 +4,7 @@ include ../Rules.mk
 XG_HDRS := xg_public.h 
 XG_OBJS := xg_main.o 
 
+CFLAGS += -D__XEN_TOOLS__
 CFLAGS += $(CFLAGS_xeninclude)
 
 
diff --git a/tools/firmware/hvmloader/Makefile b/tools/firmware/hvmloader/Makefile
index 0560a7b59a..f2f4791055 100644
--- a/tools/firmware/hvmloader/Makefile
+++ b/tools/firmware/hvmloader/Makefile
@@ -31,7 +31,7 @@ SMBIOS_REL_DATE ?= $(shell date +%m/%d/%Y)
 CFLAGS += $(CFLAGS_xeninclude)
 
 # We mustn't use tools-only public interfaces.
-CFLAGS += -U__XEN_TOOLS__ -D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__
+CFLAGS += -D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__
 
 OBJS  = hvmloader.o mp_tables.o util.o smbios.o 
 OBJS += smp.o cacheattr.o xenbus.o vnuma.o
diff --git a/tools/libxc/Makefile b/tools/libxc/Makefile
index ca8bab7233..0a8614c952 100644
--- a/tools/libxc/Makefile
+++ b/tools/libxc/Makefile
@@ -105,6 +105,7 @@ endif
 
 CFLAGS   += -Werror -Wmissing-prototypes
 CFLAGS   += -I. -I./include $(CFLAGS_xeninclude)
+CFLAGS   += -D__XEN_TOOLS__
 
 # Needed for posix_fadvise64() in xc_linux.c
 CFLAGS-$(CONFIG_Linux) += -D_GNU_SOURCE
diff --git a/tools/ocaml/libs/eventchn/xeneventchn_stubs.c b/tools/ocaml/libs/eventchn/xeneventchn_stubs.c
index b711fd8bbd..45a385dedf 100644
--- a/tools/ocaml/libs/eventchn/xeneventchn_stubs.c
+++ b/tools/ocaml/libs/eventchn/xeneventchn_stubs.c
@@ -21,7 +21,6 @@
 #include <errno.h>
 #include <stdint.h>
 #include <sys/ioctl.h>
-#include <xen/sysctl.h>
 #include <xen/xen.h>
 #include <xen/sys/evtchn.h>
 #include <xenevtchn.h>