diff --git a/libc/bionic/raise.cpp b/libc/bionic/raise.cpp
index 0dd0ad7..b134b5a 100644
--- a/libc/bionic/raise.cpp
+++ b/libc/bionic/raise.cpp
@@ -26,6 +26,7 @@
  * SUCH DAMAGE.
  */
 
+#include <errno.h>
 #include <pthread.h>
 #include <signal.h>