diff --git a/fallback.h b/fallback.h
index 5f3b1af7a..2cad4e32a 100644
--- a/fallback.h
+++ b/fallback.h
@@ -9,6 +9,8 @@
 #include <wchar.h>
 #include <limits.h>
 #include <sys/time.h>
+#include <sys/types.h>
+#include <signal.h>
 
 #ifndef WCHAR_MAX
 /**
@@ -47,6 +49,10 @@ typedef char tputs_arg_t;
 #define SIGIO SIGUSR1
 #endif
 
+#ifndef SIGWINCH
+#define SIGIO SIGUSR2
+#endif
+
 #ifndef HAVE_WINSIZE
 struct winsize 
 {