cosmetic Makefile fix

[Denys Vlasenko]

Hi Bernd,

While testing build system with some scripts I was bitten
by the cosmetic problem that make is never silent.
Even if it doesn't build anything, it says
"make[1]: `conf' is up to date". My scripts were deciding
that if make says something, it means we see spurious
rebuilds happening.

I added this TODO for now in top-level Makefile.in:

extra/config/conf extra/config/mconf: include/bits
# TODO: this results in "make[1]: `conf' is up to date" printed
# on every rebuild, because extra/config/conf is already built
# on previous make run. Make it "test -x $@ || ..." (simple & a bit wrong)
# or "make -q -C extra/config $(notdir $@) || ..." (less readable)?
        $(Q)$(MAKE) -C extra/config $(notdir $@)

In your opinion, which option would be more appropriate here?
--
vda