diff --git a/lldb/tools/debugserver/source/MacOSX/MachProcess.mm b/lldb/tools/debugserver/source/MacOSX/MachProcess.mm
index 032f2a87790373..95060c552f25a7 100644
--- a/lldb/tools/debugserver/source/MacOSX/MachProcess.mm
+++ b/lldb/tools/debugserver/source/MacOSX/MachProcess.mm
@@ -34,6 +34,7 @@
 #include <chrono>
 #include <map>
 
+#include <TargetConditionals.h>
 #import <Foundation/Foundation.h>
 
 #include "DNBDataRef.h"