Bug#613046: debian-policy: please update example in 4.9.1 (debian/rules and DEB_BUILD_OPTIONS)

[Jonathan Nieder <jrnieder@gmail.com>]

Hi,

Charles Plessy wrote:

> since §4.9.1's object is to document the DEB_BUILD_OPTIONS, I would find it a
> bit dry to only provide an example that works through a tool that is not
> mentionned or explained anywhere else in the Policy (see http://bugs.debian.org/578597).
> I therfore propose to replace the sentence above it,
>
>   The following makefile snippet is an example of how one may implement the
>   build options; you will probably have to massage this example in order to make
>   it work for your package.
>
> by:
>
>   In the following example, the build options nocheck, nostrip and parallel are
>   implemented directly in make, and noopt is implemented through its support in
>   dpkg-buildflags.  You will probably have to massage this example in order to
>   make it work for your package.  Note also that other helper tools provide
>   support for nocheck, nostrip and parallel.

By now I imagine that dpkg-buildflags is becoming enough of a de facto
standard that it would be reasonable to just recommend it with a policy
"should".  Niels, would you mind if I merge this with bug#578597?

[...]
> By the way, I read in the paragraph describing noopt:
>
>   For C programs, it is best to add -O0 to CFLAGS (although this is usually the default).
>
> Isn't that a bit outdated ?  I see -O2 or superior in most of my packages.

I believe the intended meaning is that in many build systems, if you
override CFLAGS and do not specify an optimization level then no
optimization level is passed to gcc, resulting in no optimization.

Thanks,
Jonathan