Will GNU Make automatically add additional preconditions?

The following snippet of an example is presented in "Managing Projects with GNU Make (3rd Edition)" on page 21.

count_words: counter.o lexer.o -lfl

      

        
        
        
      

    

The author says he make

will automatically add count_words.o

to the list of preconditions on an implicit rule. Quoted:

..., make identifies four prerequisites: count_words.o (this condition is not in the makefile, but is enforced by an implicit rule), counter.o, lexer.o, and -lfl.

However, my test doesn't match this. Here's my test:

prog: abc.o
    @echo $^
abc.o:
    @echo abc.o built.
prog.o:
    @echo prog.o bulit.

      

        
        
        
      

    

Exit after startup make

:

abc.o is built.

abc.o

make

not looking prog.o

for a purpose prog

. What is the problem? Is there something wrong with my test?

By the way, my test is on Cygwin

p GNU Make 4.1

.