diff --git a/src/threading.cpp b/src/threading.cpp
index 8e1ee8104..c8a15e2a6 100644
--- a/src/threading.cpp
+++ b/src/threading.cpp
@@ -1,3 +1,7 @@
+#if defined(GB_SYSTEM_UNIX)
+#include <signal.h>
+#endif
+
 struct BlockingMutex;
 struct RecursiveMutex;
 struct Semaphore;