nvim: lsp: Enable clangd for C and C++

nvim/.config/nvim/lua/lsp.lua

@@ -3,6 +3,7 @@ local protocol   = require('vim.lsp.protocol')
 local signature  = require('lsp_signature')
 local ts_utils   = require("nvim-lsp-ts-utils")
 local null_ls    = require("null-ls")
+local util       = require("lspconfig/util")
 
 -- Taken from https://www.reddit.com/r/neovim/comments/gyb077/nvimlsp_peek_defination_javascript_ttserver/
 function preview_location(location, context, before_context)
@@ -199,6 +200,21 @@ for _, lsp in ipairs(servers) do
   }
 end
 
+nvim_lsp.clangd.setup {
+  on_attach = on_attach,
+  default_config = {
+    cmd = { "clangd", "--background-index", "--pch-storage=memory", "--clang-tidy", "--suggest-missing-includes" },
+    filetypes = { 'c', 'cpp' },
+    root_dir = function(fname)
+      -- We specify build/compile_commands.json as that is where the compile_commands.json
+      -- gets generated automatically for meson projects.
+      local root_pattern = util.root_pattern('build/compile_commands.json', 'compile_commands.json', 'compile_flags.txt', '.git')
+      local filename = util.path.is_absolute(fname) and fname or util.path.join(vim.loop.cwd(), fname)
+      return root_pattern(filename) or util.path.dirname(filename)
+    end,
+  }
+}
+
 -- See https://github.com/sumneko/lua-language-server/wiki/Setting-without-VSCode#neovim-with-built-in-lsp-client
 -- on why we do this library thing
 -- Idea taken from https://gist.github.com/folke/fe5d28423ea5380929c3f7ce674c41d8