silent build rules (was: GNU M4 1.4.13 released (stable))

* Eric Blake wrote on Wed, Apr 01, 2009 at 08:52:36PM CEST:
> According to Bob Friesenhahn on 4/1/2009 12:40 PM:
> > 
> > It seems that I will need to permanently define and export the arbitrary
> > variable 'V' in my shell environment in order to avoid confusion later
> > since I won't know how a build will behave until I type 'make'.  That
> > leaves 25 more single-letter variables for my own use.

The rationale for keeping V was that users accustomed to the Linux build
system would not have to relearn.  Maybe that is not such a good
rationale: those who build the kernel regularly are hardly the least
experienced users.

Suggestions welcome.  (Hope this doesn't turn into a big bike shed.)

However, do note that you do not need to use
  env V=1 make -e

because it should suffice to use
  make V=1

as nothing in the Makefile should set V (but see below).

> > Hopefully it won't alter the behavior of other scripts or builds.

As I wrote off-list already, unless you use the 'silent-rules' option
for your packages, your code should be built as always.

> At this point, it seems like it might be a good idea for the use of
> 'automake --silent-rules' to add a configure option that sets the default
> state of the V make variable for a user's taste.  That is, you would still
> have to request automake to issue silent-rules support, but once a project
> has silent rule support, the user can still have the flexibility to choose
> the default verbosity level that they are comfortable with.  Something
> like './configure --disable-silent-rules' to request the V=1 behavior?

This is an open problem, and mentioned here:
<http://article.gmane.org/gmane.comp.sysutils.automake.patches/3408>
Suggestions welcome.

Cheers,
Ralf