'make depend' or 'make' bug on recent --current

[Andrey Chernov]

Steps to reproduce:

cd /usr/src/lib/libc/stdlib
touch *div*.c
cd ..
make depend
make

And see how imaxdiv.o only is recompiled.
No div.o ldiv.o lldiv.o are recompiled.

P.S. new make depend is simple disgusting. It tends to recompile
everything in the system if some minor header file is touched, but
completely forget to recompile source code changes. I suggest to back
out all AI in that area.
'make depend' is not time-consuming task and good old way never made
mistakes.