- Use NULL instead of 0 for all non-handle pointers.
- Fix non-ANSI function declarations.
- Make a function static.

diff --git a/server/signal.c b/server/signal.c
index 470a476..f3b0f5f 100644
--- a/server/signal.c
+++ b/server/signal.c
@@ -181,25 +181,25 @@
 }
 
 /* SIGHUP handler */
-static void do_sighup()
+static void do_sighup( int signum )
 {
     do_signal( handler_sighup );
 }
 
 /* SIGTERM handler */
-static void do_sigterm()
+static void do_sigterm( int signum )
 {
     do_signal( handler_sigterm );
 }
 
 /* SIGINT handler */
-static void do_sigint()
+static void do_sigint( int signum )
 {
     do_signal( handler_sigint );
 }
 
 /* SIGCHLD handler */
-static void do_sigchld()
+static void do_sigchld( int signum )
 {
     do_signal( handler_sigchld );
 }