ARM64: fix libxl build, do not include ../../xen/include

Do not include ../../xen/include/ to build libxl_arm_acpi.c: header
files clashing against default headers under /usr/include are present in
that directory.

Link only $(XEN_ROOT)/xen/include/acpi under tools/include instead.

Build tested on ARM64 and x86_64.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Tested-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Wei Liu <wei.liu2@citrix.com>

tools/include/Makefile

@@ -20,6 +20,7 @@ xen/.dir:
 	ln -sf ../xen-sys/$(XEN_OS) xen/sys
 	ln -sf $(addprefix $(XEN_ROOT)/xen/include/xen/,libelf.h elfstructs.h) xen/libelf/
 	ln -s ../xen-foreign xen/foreign
+	ln -s $(XEN_ROOT)/xen/include/acpi acpi
 	touch $@
 
 # Not xen/xsm as that clashes with link to

tools/libxl/Makefile

@@ -96,7 +96,7 @@ dsdt_anycpu_arm.c:
 	$(MAKE) -C $(ACPI_PATH) ACPI_BUILD_DIR=$(CURDIR)
 
 libxl_arm_acpi.o: libxl_arm_acpi.c
-	$(CC) -c $(CFLAGS) -I../../xen/include/ -o $@ libxl_arm_acpi.c
+	$(CC) -c $(CFLAGS) -o $@ libxl_arm_acpi.c
 else
 LIBXL_OBJS-$(CONFIG_ARM) += libxl_arm_no_acpi.o
 endif