diff --git a/nmap.cc b/nmap.cc
index 132e58532..5dea08801 100644
--- a/nmap.cc
+++ b/nmap.cc
@@ -151,6 +151,10 @@
 #include "nse_main.h"
 #endif
 
+#ifdef HAVE_SIGNAL
+#include <signal.h>
+#endif
+
 #ifdef WIN32
 #include "winfix.h"
 /* This name collides in the following include. */