Allow the include directive.

* The include directive is ignored for now here.

Bug: 112259977
Test: ./checkowners.py  -v -c OWNERS
Change-Id: I671f3643ea88e50aea0957db59c36f10bff3b92d
diff --git a/tools/checkowners.py b/tools/checkowners.py
index 8568ccf..7f03968 100755
--- a/tools/checkowners.py
+++ b/tools/checkowners.py
@@ -56,7 +56,8 @@
   glob = '[a-zA-Z0-9_\\.\\-\\*\\?]+'
   globs = '(%s( *, *%s)*)' % (glob, glob)
   perfile = 'per-file +' + globs + ' *= *' + directive
-  pats = '(|%s|%s|%s)$' % (noparent, email, perfile)
+  include = 'include +([^ :]+ *: *)?[^ ]+'
+  pats = '(|%s|%s|%s|%s)$' % (noparent, email, perfile, include)
   patterns = re.compile(pats)
   address_pattern = re.compile('([^@ ]+@[^ @]+)')
   perfile_pattern = re.compile('per-file +.*=(.*)')