diff --git a/libc/include/signal.h b/libc/include/signal.h
index f1849c5..e23e65b 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -48,6 +48,9 @@
 #  include <linux/signal.h>
 #endif
 
+#include <sys/ucontext.h>
+#define __BIONIC_HAVE_UCONTEXT_T
+
 __BEGIN_DECLS
 
 typedef int sig_atomic_t;