`ninja check` failed in building libxml2

any way to solve this problem?

```
$ ninja check
...
[65/73] Linking CXX executable examples/libxml2/libxml2_example
FAILED: examples/libxml2/libxml2_example
: && /usr/bin/clang++ -fno-exceptions -Werror -Wall -Wstring-conversion -g -fsanitize=fuzzer examples/libxml2/CMakeFiles/libxml2_example.dir/libxml2_example.cc.o -o examples/libxml2/libxml2_example examples/xml/libprotobuf-mutator-xml.a examples/libxml2/external.libxml2/lib/libxml2.a /usr/lib/x86_64-linux-gnu/libz.so /usr/lib/x86_64-linux-gnu/liblzma.so src/libfuzzer/libprotobuf-mutator-libfuzzer.a src/libprotobuf-mutator.a external.protobuf/lib/libprotobufd.a && :
clang: error: no such file or directory: 'examples/libxml2/external.libxml2/lib/libxml2.a'
[67/73] Linking CXX executable examples/libfuzzer/libfuzzer_bin_example
ninja: build stopped: subcommand failed.
```

os version:

```
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal
```

clang++ version:

```
clang version 10.0.0-4ubuntu1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
```