Autogenerate dependencies when using make.

The list of file dependencies have grown a little big and the Makefile
is constantly outdated. Replace the explicit dependencies with an
automatic rule that regenerates all the dependencies before compiling.

The Makefile is only used by developers since Android uses Android.bp
and Chromium uses the bsdiff.gyp.

Bug: None
Test: make; modify a file; make
Change-Id: I464729fa32aa4d9be086205ac4be58d9dd5a70d1