Make sure signal.h is #include'd when needed

src/ngircd/irc-login.c

@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
+#include <signal.h>
 #include <unistd.h>
 
 #include "ngircd.h"

src/ngircd/resolve.c

@@ -23,6 +23,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netdb.h>
+#include <signal.h>
 
 #ifdef IDENTAUTH
 #ifdef HAVE_IDENT_H