Add some missing #includes that weren't required due to namespace polution

in our headers.

Submitted by: bde

usr.sbin/ppp/main.c

@@ -43,6 +43,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/time.h>
 #include <termios.h>
 #include <unistd.h>
 #include <sys/stat.h>

usr.sbin/ppp/sig.c

@@ -26,6 +26,8 @@
  * $FreeBSD$
  */
 
+#include <sys/types.h>
+
 #include <signal.h>
 
 #include "log.h"

usr.sbin/ppp/timer.c

@@ -32,9 +32,7 @@
 #include <signal.h>
 #include <stdio.h>
 #include <string.h>
-#ifdef __NetBSD__
 #include <sys/time.h>
-#endif
 #include <termios.h>
 
 #include "log.h"