stubdom: foreignmemory: Fix build after 0dbb4be739c5

stubdom: foreignmemory: Fix build after 0dbb4be739c5

Commit 0dbb4be739c5 add the inclusion of xenctrl.h from private.h and
wreck the build in an interesting way:

In file included from xen/stubdom/include/xen/domctl.h:39:0,
                 from xen/tools/include/xenctrl.h:36,
                 from private.h:4,
                 from minios.c:29:
xen/include/public/memory.h:407:5: error: expected specifier-qualifier-list before ‘XEN_GUEST_HANDLE_64’
     XEN_GUEST_HANDLE_64(const_uint8) buffer;
     ^~~~~~~~~~~~~~~~~~~

This is happening because xenctrl.h defines __XEN_TOOLS__ and therefore
the public headers will start to expose the non-stable ABI. However,
xen.h has already been included by a mini-OS header before hand. So
there is a mismatch in the way the headers are included.

For now solve it in a very simple (and gross) way by including
xenctrl.h before the mini-os headers.

Fixes: 0dbb4be739c5 ("tools/libs/foreignmemory: Fix PAGE_SIZE redefinition error")
Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>