[thirdparty] fix LLVM compilation on Ubuntu 20.04

This changelist adds a patch from the llvm-toolchain-9-9.0.1 Debian
source package to fix compilation of LLVM 9.0 in Kudu thirdparty
on Ubuntu 20.04 LTS.  See [1], [2] for the original source of the patch.

The patch is already included in the upstream LLVM repo and included
into 10.0.0 and later releases.

[1] https://reviews.llvm.org/rG947f9692440
[2] https://github.com/llvm/llvm-project/commit/947f9692440836dcb8d88b74b69dd379d85974ce

Change-Id: Ifba0bf6ba660a536ed54ddce228a38470dd1c650
Reviewed-on: http://gerrit.cloudera.org:8080/16477
Tested-by: Kudu Jenkins
Reviewed-by: Grant Henke <granthenke@apache.org>
2 files changed