Include less of the generated modular QAPI headers

In my "build everything" tree, a change to the types in
qapi-schema.json triggers a recompile of about 4800 out of 5100
objects.

The previous commit split up qmp-commands.h, qmp-event.h, qmp-visit.h,
qapi-types.h.  Each of these headers still includes all its shards.
Reduce compile time by including just the shards we actually need.

To illustrate the benefits: adding a type to qapi/migration.json now
recompiles some 2300 instead of 4800 objects.  The next commit will
improve it further.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180211093607.27351-24-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[eblake: rebase to master]
Signed-off-by: Eric Blake <eblake@redhat.com>
diff --git a/backends/hostmem.c b/backends/hostmem.c
index 8aa0412..74fc04a 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -9,12 +9,13 @@
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
  */
+
 #include "qemu/osdep.h"
 #include "sysemu/hostmem.h"
 #include "hw/boards.h"
 #include "qapi/error.h"
+#include "qapi-builtin-visit.h"
 #include "qapi/visitor.h"
-#include "qapi-visit.h"
 #include "qemu/config-file.h"
 #include "qom/object_interfaces.h"