Figure 11: An alternate target clean.
The most useful property of make is that we can automatically
create object files and executables.
Another useful property is that we can easily tell make how to
clean them up.
In order to do this, we need to specify an alternate target clean,
as shown in Figure 11.
We need not give a definition of RM, because make expands
it to rm -f by default.
The alternate rule may be placed anywhere, as long as it is after the
rule for facfib.
If we place it before facfib and we type ``make'', make
picks the first target, which will be clean instead of facfib.
clean has no dependencies, so if we type ``make clean'',
make executes the command at the next line
.
It is good practice to provide a target clean to clean up all generated
files.