When I run make it evaluates a lot of targets based on the dependency rules.  What I would like is a way to have the dispatch of unrelated things occur in an order sorted based on file timestamps.  Example, suppose I have

prog: a.o b.o c.o d.o e.o f.o
  ...
%.o: %.cpp shared.h
  ...

If I modify shared.h everything will recompile.  If that was all I modified, I don't care what order they recompile.  But if I also modified d.cpp at the same time, I would like it to choose to dispatch d.cpp as early as possible, in preference to the other .cpp files.

Since I have a single giant makefile for a very large source tree, it is very difficult for me to reorder the rules to accomplish this.  But when I have touched one header and (say) three scattered source files, getting them to compile first could often save a lot of time.