Fails here:
https://build.opensuse.org/build/openSUSE:Factory:Staging:Gcc7/standard/x86_64/xtrabackup/_log

with:

[  471s]     inlined from 'virtual String*
Item_func_format::val_str_ascii(String*)' at
/home/abuild/rpmbuild/BUILD/percona-xtrabackup-2.4.12/sql/item_strfunc.cc:3214:13:
[  471s] /usr/include/bits/string_fortified.h:34:33: warning: 'void*
__builtin_memcpy(void*, const void*, long unsigned int)' writing 1 or more
bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
[  471s]    34 |   return __builtin___memcpy_chk (__dest, __src, __len, __bos0
(__dest));
[  471s]       |         
~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[  471s] [ 80%] Building CXX object sql/CMakeFiles/sql.dir/item_sum.cc.o