build: Load makefiles in the same order with Make 4.0

Make 4.0 (and Kati) removed the implicit sort from the $(wildcard)
function. In order to ensure that makefiles are always loaded in the
same order, and an explicit sort.

This shouldn't matter, but some makefiles are modifying variables used
by siblings (LLVM_ROOT_PATH under frameworks/compile). In this case, the
path value still pointed to the same path, it just had extra '..'
references, and was enough to cause the binaries to be different.

Change-Id: Ief6551f999351ee2c193275aaae426dc064f8b34