diff --git a/src/exec_common.c b/src/exec_common.c
index a4cd5400b..ff06dabd4 100644
--- a/src/exec_common.c
+++ b/src/exec_common.c
@@ -40,6 +40,7 @@
 # include <priv.h>
 #endif
 #include <errno.h>
+#include <signal.h>
 
 #include "sudo.h"
 #include "sudo_exec.h"
diff --git a/src/sesh.c b/src/sesh.c
index d6b56c3c5..e6d57e5e4 100644
--- a/src/sesh.c
+++ b/src/sesh.c
@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <signal.h>
 #include <unistd.h>
 #ifdef HAVE_SETLOCALE
 # include <locale.h>
diff --git a/src/utmp.c b/src/utmp.c
index 427cdc50f..91ff144dd 100644
--- a/src/utmp.c
+++ b/src/utmp.c
@@ -53,6 +53,7 @@
 # include <ttyent.h>
 #endif
 #include <fcntl.h>
+#include <signal.h>
 
 #include "sudo.h"
 #include "sudo_exec.h"