Edits to help support repo:onf-make as a git submodule.

transition.mk
-------------
  o Basic bridge logic for transition to repo:onf-make.
  o Include costs.mk and virtualenv targets.
  o Conditional include.mk logic to inline into Makefile
    appended at the end.

makefiles/detect
----------------
  o WIP
  o Add detection logic to enable makefile features based on extension.
  o Targets and logic can be loaded on demand based on available source.
    VS kitchen sink/load everything that happens now.

Signed-off-by: Joey Armstrong <jarmstrong@linuxfoundation.org>
Change-Id: I0d9af7bc15d7556ae7e15c5410b36189160c875d
diff --git a/Makefile b/Makefile
index b6cd637..4a7ca9f 100644
--- a/Makefile
+++ b/Makefile
@@ -30,6 +30,8 @@
 onf-mk-top    := $(dir $(onf-mk-abs))
 onf-mk-top    := $(patsubst %/,%,$(onf-mk-top))
 
+onf-mk-dir    := $(onf-mk-top)/makefiles
+
 ##-------------------##
 ##---]  GLOBALS  [---##
 ##-------------------##
@@ -39,7 +41,7 @@
 ##---]  INCLUDES  [---##
 ##--------------------##
 include config.mk
-include $(onf-mk-top)/makefiles/include.mk
+include $(onf-mk-dir)/include.mk
 
 ## -----------------------------------------------------------------------
 ## Intent: Helper target for interactive README.md viewing