chg: silence warning of unused parameter 'sig'

contrib/chg/chg.c

@@ -381,7 +381,7 b' error:'
 	abortmsgerrno("failed to handle stop signal");
 }
 
-static void handlechildsignal(int sig)
+static void handlechildsignal(int sig UNUSED_)
 {
 	if (peerpid == 0 || pagerpid == 0)
 		return;

contrib/chg/util.h

@@ -12,8 +12,10 b''
 
 #ifdef __GNUC__
 #define PRINTF_FORMAT_ __attribute__((format(printf, 1, 2)))
+#define UNUSED_ __attribute__((unused))
 #else
 #define PRINTF_FORMAT_
+#define UNUSED_
 #endif
 
 void abortmsg(const char *fmt, ...) PRINTF_FORMAT_;