Xenial image includes broken clang compiler

xenial images include clang:

clang version 7.0.0 (tags/RELEASE_700/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/clang-7.0.0/bin

however, using clang -flto crashes:

/usr/bin/ld: /usr/local/clang-7.0.0/bin/…/lib/LLVMgold.so: error loading plugin: /usr/local/clang-7.0.0/bin/…/lib/LLVMgold.so: cannot open shared object file: No such file or directory
clang-7: error: linker command failed with exit code 1 (use -v to see invocation)