Fix a missing dependency that can result in:

../libpcap-1.8.1/grammar.y:78:10: fatal error: scanner.h: No such file or directory

Upstream-Status: Backport
Signed-off-by: Ross Burton <ross.burton@intel.com>

From 0dd90a6bdbce4dca14106859eee63ef643a106e2 Mon Sep 17 00:00:00 2001
From: Alfredo Alvarez Fernandez <alfredoalvarezernandez@gmail.com>
Date: Tue, 21 Feb 2017 11:41:43 +0100
Subject: [PATCH] Makefile.in: Fix missing dependency

---
 Makefile.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile.in b/Makefile.in
index 7044f043..f5d443ae 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -465,7 +465,7 @@ grammar.h: grammar.c
 		$(MAKE) $(MAKEFLAGS) grammar.c; \
 	fi
 
-grammar.o: grammar.c
+grammar.o: grammar.c scanner.h
 	$(CC) $(FULL_CFLAGS) -c grammar.c
 
 gencode.o: $(srcdir)/gencode.c grammar.h scanner.h