[scripts] add the tagit script back, which got dropped from repo move

Looks like an old .gitignore line made it fall out of the transfer.
Remove that line.

Change-Id: I6c6efbbfb82b99f521dbdecc41988a88dfdf08d1

.gitignore

@@ -8,7 +8,6 @@ local.mk
 cscope.*
 doit
 t
-tagit
 blk.bin
 /gn
 *.dSYM

scripts/tagit

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+# Copyright 2016 The Fuchsia Authors
+# Copyright (c) 2008 Travis Geiselbrecht
+#
+# Use of this source code is governed by a MIT-style
+# license that can be found in the LICENSE file or at
+# https://opensource.org/licenses/MIT
+
+if [ "$#" -lt 1 ]; then
+    FILES=`find . -type f -regex ".*\.[chS]\|.*\.cpp"`
+    echo running ctags
+    rm -f tags
+    echo $FILES | xargs ctags -a
+else
+    if [ ! -d build-$1 ]; then
+        echo "directory build-$1 does not exist"
+        exit 1
+    fi
+    echo running ctags on project $1
+    rm -f tags
+    ctags -L build-$1/srcfiles.txt
+    ctags -a --recurse -L build-$1/include_paths.txt 2> /dev/null
+fi