Add "check-includes" to check-local.

Makefile.am

@@ -197,7 +197,7 @@ doxygen:
 test: all
 	$(top_builddir)/src/test/test
 
-check-local: check-spaces check-changes
+check-local: check-spaces check-changes check-includes
 
 need-chutney-path:
 	@if test ! -d "$$CHUTNEY_PATH"; then \

changes/ticket26447

@@ -0,0 +1,5 @@
+  o Minor features (code correctness, testing):
+    - Tor's build process now includes a "check-includes" make target
+      to verify that no module of Tor relies on any headers from a
+      higher-level module. We hope to use this feature over time to
+      help refactor our codebase.  Closes ticket 26447.