@@ I was thinking about the way make handles inclusion of missing
   makefile. The following strategy seems like a better choice: 
   if makefile is missing try to rebuild & read it immediately,
   without parsing the rest of makefile and without reexecuting
   make later. This approach has at least two benefits:
   
    + more efficient (no make re-execution) (this is not very
      important in most cases, thoug)
      
    + more deterministic: if some of the code after (missing)
      included makefile depends on some code from it (for
      example a function) then things can break (example:
      configuration of ORB).

    - sequential (cannot build makefile in parallel)
    
    
@! target/pattern-specific vpath
        
@@ no `target is up to date' message when commnds are executed
   but target is not changed.

@@ %.o %.d and include

%% implicit double expansion: now supports target/pattern variables
   and $-
   
%% create `examples' directory where I can put md5 and maybe hello.

@! shortest stem