🚀 go-pugleaf

This is not a bug.  You have misunderstood how Make works.  Variables and
functions in rule targets and dependencies are expanded when the makefile
is read.

> Makefile used (contains 1 line):
> l.m : % : $(basename %).c
> 
> Result obtained in a directory containing only the Makefile file:
> make: *** No way to make target `l.m.c'.  Stop.
> 
> Result expected:
> make: *** No way to make target `l.c'.  Stop.
> 
> Comments:
> why is the basename function not executed?
> If the Makefile is: 
> l.m : % : $(addsuffix i,%).c
> the result is:
> make: *** No way to make target `l.mi.c'.  Stop.
> That shows that it is possible to use a function in a static pattern rule.
> Why does not it work with basename?

In your second makefile, the function is expanded at read time and results in:

l.m: %: %i.c

In the first, `$(basename %)' becomes `%', so the rule is:

l.m: %: %.c