https://github.com/MaskRay/ccls/commit/dce86b1362acbabb8f997869fdaa27adc67f9a55.patch
https://bugs.gentoo.org/835916

From: Fangrui Song <i@maskray.me>
Date: Wed, 15 Dec 2021 10:13:29 -0800
Subject: [PATCH] cmake: Add LANGUAGE C to fix find_package(Clang REQUIRED)
 error

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.8)
-project(ccls LANGUAGES CXX)
+project(ccls LANGUAGES CXX C)
 
 option(USE_SYSTEM_RAPIDJSON "Use system RapidJSON instead of the git submodule if exists" ON)