diff --git a/libc/bionic/pthread_exit.cpp b/libc/bionic/pthread_exit.cpp
index aa9bd38..cc86271 100644
--- a/libc/bionic/pthread_exit.cpp
+++ b/libc/bionic/pthread_exit.cpp
@@ -28,6 +28,7 @@
 
 #include <pthread.h>
 
+#include <signal.h>
 #include <stdlib.h>
 #include <sys/mman.h>