diff --git a/llvm/lib/Object/ArchiveWriter.cpp b/llvm/lib/Object/ArchiveWriter.cpp
--- a/llvm/lib/Object/ArchiveWriter.cpp
+++ b/llvm/lib/Object/ArchiveWriter.cpp
@@ -34,6 +34,7 @@
 #include "llvm/Support/SmallVectorMemoryBuffer.h"
 #include "llvm/Support/raw_ostream.h"
 
+#include <cerrno>
 #include <map>
 
 #if !defined(_MSC_VER) && !defined(__MINGW32__)
diff --git a/llvm/lib/Support/JSON.cpp b/llvm/lib/Support/JSON.cpp
--- a/llvm/lib/Support/JSON.cpp
+++ b/llvm/lib/Support/JSON.cpp
@@ -14,6 +14,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/NativeFormatting.h"
 #include <cctype>
+#include <cerrno>
 #include <optional>
 
 namespace llvm {
diff --git a/llvm/lib/Support/Path.cpp b/llvm/lib/Support/Path.cpp
--- a/llvm/lib/Support/Path.cpp
+++ b/llvm/lib/Support/Path.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Signals.h"
 #include <cctype>
+#include <cerrno>
 
 #if !defined(_MSC_VER) && !defined(__MINGW32__)
 #include <unistd.h>