Compilation failed `fs/xfs/libxfs/xfs_alloc.c:20` using `repo` and `buildroot`

[DamonBlais]

Following, this time, the instructions over here: http://rockchip.wikidot.com/linux-user-guide

$ mkdir rk-bb
$ cd rk-bb
$ repo init -u https://github.com/rockchip-linux/manifests -b buildroot
$ repo sync
$ build/mk-kernel.sh rk3399-excavator

Which results in:

  CC      fs/locks.o                                                                                                                                                     
In file included from fs/xfs/libxfs/xfs_alloc.c:20:                                                                                                                      
fs/xfs/libxfs/xfs_alloc.c: In function 'xfs_alloc_get_freelist':                                                                                                         
fs/xfs/libxfs/xfs_format.h:768:3: warning: taking address of packed member of 'struct xfs_agfl' may result in an unaligned pointer value [-Waddress-of-packed-member]
error, forbidden warning:xfs_format.h:768                                           
  768 |   &(XFS_BUF_TO_AGFL(bp)->agfl_bno[0]) : \                                                                                                                        
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                                                                                                            
fs/xfs/libxfs/xfs_alloc.c:2207:13: note: in expansion of macro 'XFS_BUF_TO_AGFL_BNO' 
 2207 |  agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
      |             ^~~~~~~~~~~~~~~~~~~                                             
fs/xfs/libxfs/xfs_alloc.c: In function 'xfs_alloc_put_freelist':                                                                                                         
fs/xfs/libxfs/xfs_format.h:768:3: warning: taking address of packed member of 'struct xfs_agfl' may result in an unaligned pointer value [-Waddress-of-packed-member]
error, forbidden warning:xfs_format.h:768
  768 |   &(XFS_BUF_TO_AGFL(bp)->agfl_bno[0]) : \
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/xfs/libxfs/xfs_alloc.c:2338:13: note: in expansion of macro 'XFS_BUF_TO_AGFL_BNO' 
 2338 |  agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
      |             ^~~~~~~~~~~~~~~~~~~
  CC      fs/compat.o
  CC      fs/compat_ioctl.o
  CC      fs/binfmt_script.o
  CC      fs/binfmt_elf.o
  CC      fs/compat_binfmt_elf.o
  CC      fs/nfs/read.o
  CC      fs/mbcache.o
make[2]: *** [scripts/Makefile.build:277: fs/xfs/libxfs/xfs_alloc.o] Error 1
make[2]: *** Deleting file 'fs/xfs/libxfs/xfs_alloc.o'
make[2]: *** Waiting for unfinished jobs....

System compiled on:

$ gcc --version
gcc (GCC) 9.2.1 20190827 (Red Hat 9.2.1-1)
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ g++ --version
g++ (GCC) 9.2.1 20190827 (Red Hat 9.2.1-1)
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ cat /etc/redhat-release 
Fedora release 31 (Thirty One)

$ uname -a
Linux doom2 5.3.12-300.fc31.x86_64 #1 SMP Thu Nov 21 22:52:07 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

cross-compiler is aarch64-linux-gnu-gcc

$ aarch64-linux-gnu-gcc --version
aarch64-linux-gnu-gcc (GCC) 9.2.1 20190827 (Red Hat Cross 9.2.1-1)
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Provided by:

$ dnf info gcc-aarch64-linux-gnu
Installed Packages
Name         : gcc-aarch64-linux-gnu
Version      : 9.2.1
Release      : 1.fc31
Architecture : x86_64
Size         : 55 M
Source       : cross-gcc-9.2.1-1.fc31.src.rpm