vtysh: drop unused variables & RETSIGTYPE

Drop unused return values in vtysh.  Also gets rid of the rather funny
prototyping of signal setup in vtysh - which as a side effect makes it
not need AC_TYPE_SIGNAL in configure.ac anymore.  It wasn't used
sensibly to begin with...

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/vtysh/vtysh.c b/vtysh/vtysh.c
index d64b4e0..fbbc88d 100644
--- a/vtysh/vtysh.c
+++ b/vtysh/vtysh.c
@@ -1713,7 +1713,6 @@
        "Write to terminal\n")
 {
   u_int i;
-  int ret;
   char line[] = "write terminal\n";
   FILE *fp = NULL;
 
@@ -1735,7 +1734,7 @@
   vty_out (vty, "!%s", VTY_NEWLINE);
 
   for (i = 0; i < array_size(vtysh_client); i++)
-    ret = vtysh_client_config (&vtysh_client[i], line);
+    vtysh_client_config (&vtysh_client[i], line);
 
   /* Integrate vtysh specific configuration. */
   vtysh_config_write ();
@@ -1783,7 +1782,6 @@
 write_config_integrated(void)
 {
   u_int i;
-  int ret;
   char line[] = "write terminal\n";
   FILE *fp;
   char *integrate_sav = NULL;
@@ -1809,7 +1807,7 @@
     }
 
   for (i = 0; i < array_size(vtysh_client); i++)
-    ret = vtysh_client_config (&vtysh_client[i], line);
+    vtysh_client_config (&vtysh_client[i], line);
 
   vtysh_config_dump (fp);
 
@@ -1948,7 +1946,6 @@
 execute_command (const char *command, int argc, const char *arg1,
 		 const char *arg2)
 {
-  int ret;
   pid_t pid;
   int status;
 
@@ -1967,13 +1964,13 @@
       switch (argc)
 	{
 	case 0:
-	  ret = execlp (command, command, (const char *)NULL);
+	  execlp (command, command, (const char *)NULL);
 	  break;
 	case 1:
-	  ret = execlp (command, command, arg1, (const char *)NULL);
+	  execlp (command, command, arg1, (const char *)NULL);
 	  break;
 	case 2:
-	  ret = execlp (command, command, arg1, arg2, (const char *)NULL);
+	  execlp (command, command, arg1, arg2, (const char *)NULL);
 	  break;
 	}
 
@@ -1985,7 +1982,7 @@
     {
       /* This is parent. */
       execute_flag = 1;
-      ret = wait4 (pid, &status, 0, NULL);
+      wait4 (pid, &status, 0, NULL);
       execute_flag = 0;
     }
   return 0;