path specified in SOURCE definition

[Fausto Sanchez]

Hi,

Some or our developers have created their Makefile.am as such:

bin_PROGRAMS = foo

foo_SOURCES = foo.c foo.h bar/bar.c bar/bar.h

Is it illegal to use paths in your source definition, I couldn't find anything
in the book on this. If this is illegal how does one go about doing something
like the above if the developers insist it to be done this way. Is it just 
a matter of
creating another Makefile.am in the sub-directory, create a convenience
library and link the executable with it?

thanks in advance,
fausto..