diff --git a/connect.c b/connect.c
index db7342e4d2..66e78a2905 100644
--- a/connect.c
+++ b/connect.c
@@ -8,6 +8,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netdb.h>
+#include <signal.h>
 
 static char *server_capabilities = NULL;
 
diff --git a/merge-index.c b/merge-index.c
index 190e12fb7c..0498a6f45e 100644
--- a/merge-index.c
+++ b/merge-index.c
@@ -1,5 +1,6 @@
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <signal.h>
 
 #include "cache.h"