Add TAGS files (produced by 'make tags') to .gitignore file.

Change-Id: If5592cb0b5de018b7b9c06955f2e34d1f666530e
diff --git a/.gitignore b/.gitignore
index 3481bad..4def47a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,8 @@
 *.gcda
 *.gcno
 
+**/TAGS
+
 #configure
 aclocal.m4
 autom4te.cache/