Use "include" instead of "-include" wherever appropriate

* When using "-include", make ignores a makefile which does not
  exist, with no error message.
* Use "include" for all makefiles which are essential for a
  working build.

Change-Id: Ic00ba2e9246da3ec47102f79b9c2725ed155b4cf
(cherry picked from commit 7fc927b48cd1f1db7a815340bc7821865d3a1aef)