zsmalloc build fails without CONFIG_COMPACTION

Hi,

I'm hitting this build failure with today's master (26538100499460ee81546a0dc8d6f14f5151d427):

CC mm/zsmalloc.o
In file included from ./include/linux/mmzone.h:10:0,

                 from ./include/linux/gfp.h:6,
                 from ./include/linux/umh.h:4,
                 from ./include/linux/kmod.h:9,
                 from ./include/linux/module.h:13,
                 from mm/zsmalloc.c:33:
mm/zsmalloc.c: In function ‘zs_create_pool’:
mm/zsmalloc.c:2415:27: error: ‘struct zs_pool’ has no member named ‘migration_wait’
  init_waitqueue_head(&pool->migration_wait);
                           ^
./include/linux/wait.h:67:26: note: in definition of macro ‘init_waitqueue_head’
   __init_waitqueue_head((wq_head), #wq_head, &__key);  \
                          ^~~~~~~

make[1]: *** [scripts/Makefile.build:281: mm/zsmalloc.o] Error 1
make: *** [Makefile:1083: mm] Error 2

It looks like this is due to:
701d678599d0 ("mm/zsmalloc.c: fix race condition in zs_destroy_pool")

Cheers, David