os directory in src/Makefile.tmpl

[mc...@us.ibm.com]

At the end of src/Makefile.tmpl, in the buildmark.o and modules.o sections,
the os/unix/os.h file is referenced.
I am curious why this is specifically the os/unix directory and not
$(OSDIR) as is used in the rest of the Makefile.
The reason I noticed this is that make errors out on TPF (and I presume
other non-UNIX systems) if os/unix/os.h is not present.
It seems odd to me that os/unix/os.h is used for modules.o and buildmark.o
but os/tpf/os.h (or os/some other non-unix system dir/os.h) for everything
else.
Is this a bug or a 'feature'?

-David McCreedy
McCreedy@us.ibm.com