Comment 0 for bug 1944613

Failed to build on B/linux-hwe-5.4 5.4.0-85.95~18.04.1. This was observed in previous cycles.
I am working on a fix for it right now.

  13203 fuse_test.c:63:8: error: unknown type name ‘__u64’
      13204 static __u64 mfd_assert_get_seals(int fd)
      13205 ^~~~~
      13206 fuse_test.c:76:42: error: unknown type name ‘__u64’; did you mean ‘__f64’?
      13207 static void mfd_assert_has_seals(int fd, __u64 seals)
      13208 ^~~~~
      13209 __f64
      13210 fuse_test.c:88:42: error: unknown type name ‘__u64’; did you mean ‘__f64’?
      13211 static void mfd_assert_add_seals(int fd, __u64 seals)
      13212 ^~~~~
      13213 __f64
      13214 fuse_test.c:102:39: error: unknown type name ‘__u64’; did you mean ‘__f64’?
      13215 static int mfd_busy_add_seals(int fd, __u64 seals)
      13216 ^~~~~
      13217 __f64
      13218 fuse_test.c: In function ‘sealing_thread_fn’:
      13219 fuse_test.c:185:6: warning: implicit declaration of function ‘mfd_busy_add_seals’; did you mean ‘mfd_assert_get_seals’? [-Wimplicit-function-declaration]
      13220 r = mfd_busy_add_seals(global_mfd, F_SEAL_WRITE);
      13221 ^~~~~~~~~~~~~~~~~~
      13222 mfd_assert_get_seals
      13223 fuse_test.c:193:3: warning: implicit declaration of function ‘mfd_assert_add_seals’; did you mean ‘mfd_assert_get_seals’? [-Wimplicit-function-declaration]
      13224 mfd_assert_add_seals(global_mfd, F_SEAL_WRITE);
      13225 ^~~~~~~~~~~~~~~~~~~~
      13226 mfd_assert_get_seals
      13227 fuse_test.c: In function ‘main’:
      13228 fuse_test.c:302:2: warning: implicit declaration of function ‘mfd_assert_has_seals’; did you mean ‘mfd_assert_get_seals’? [-Wimplicit-function-declaration]
      13229 mfd_assert_has_seals(mfd, F_SEAL_WRITE);
      13230 ^~~~~~~~~~~~~~~~~~~~
      13231 mfd_assert_get_seals
      13232 make[1]: *** [/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/memfd/fuse_test] Error 1
      13233 make: *** [all] Error 2