diff --git a/llvm/lib/Support/CachePruning.cpp b/llvm/lib/Support/CachePruning.cpp
index bd42bef..6184ba2 100644
--- a/llvm/lib/Support/CachePruning.cpp
+++ b/llvm/lib/Support/CachePruning.cpp
@@ -22,6 +22,7 @@
 #define DEBUG_TYPE "cache-pruning"
 
 #include <set>
+#include <system_error>
 
 using namespace llvm;