tools/x86: don't rebuild cpuid-autogen.h every time

The first thing the "xen-dir" rule does is delete the entire xen/
subtree. Obviously this includes deleting xen/lib/x86/*autogen.h. As a
result there's no original version for $(move-if-changed ...) to compare
against, and hence the file and all its consumers would get rebuilt
every time. Instead only find and delete all the symlinks.

Fixes: eddf955 ("libx86: generate cpuid-autogen.h in the libx86 include dir")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Ian Jackson <iwj@xenproject.org>
Release-Acked-by: Ian Jackson <iwj@xenproject.org>

tools/include/Makefile

@@ -19,8 +19,8 @@ xen-foreign:
 	$(MAKE) -C xen-foreign
 
 xen-dir:
-	@rm -rf xen acpi
 	mkdir -p xen/libelf acpi
+	find xen/ acpi/ -type l -exec rm '{}' +
 	ln -s $(XEN_ROOT)/xen/include/public/COPYING xen/
 	ln -s $(XEN_ROOT)/xen/include/public/*.h xen/
 	ln -s $(XEN_ROOT)/xen/include/public/*/ xen/