core: Support GNU make 4.0 and any future releases

http://lists.gnu.org/archive/html/make-w32/2013-10/msg00021.html

Change-Id: Iaf6aa32e64269bf0368c20b0393e3fcfa540558d

Conflicts:
	core/main.mk

 Author:    Richard Bankole <rickoslyder@gmail.com>
 Changes to be committed:
	modified:   core/main.mk