Major Description
In KUDU-3334, we started hiding libprotobuf symbols in kudu client to avoid conflicts with Impala. LLD and Mold use a slightly different semantic for --exclude-libs and it won't work unless we also add the ".a" extension. Impala had an issue like that when we started supporting Mold (see the fix in IMPALA-12807 here: https://github.com/apache/impala/commit/88dcdfd4662d0ec4a6e0d81d643d207f6e5ed900 ).
The fix is to add the ".a" extension (which also works on gold).
This only comes up if Impala builds Kudu with Clang/LLD, which we currently never do. I only found this through experimentation.