[clangd] Fix missing include from r347538 - fix windows buildbots

llvm-svn: 347554

diff --git a/clang-tools-extra/clangd/index/Background.cpp b/clang-tools-extra/clangd/index/Background.cpp
index 1f850eb..9d82e65 100644 (file)
--- a/clang-tools-extra/clangd/index/Background.cpp
+++ b/clang-tools-extra/clangd/index/Background.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/SHA1.h"
 
 #include <memory>
+#include <numeric>
 #include <queue>
 #include <random>
 #include <string>