Porters Handbook: Fix typo, add a bit of detail to verbose builds `do'

[AMDmi3]

Summary

As suggested by koobs@,

• Fix typo
• Add an example of how verbose builds may be enabled for some ports

[koobs]

en_US.ISO8859-1/books/porters-handbook/porting-dads/chapter.xml

349

• MAKE_ARGS not ENV (based on my experience, only the former works)
• Clarify that it will only work for Makefiles that support or use the variable

Something like:

such as adding <literal>V=1</literal> to <varname>MAKE_ARGS</varname> for Makefile's that use the variable to mute/unmute commands depending on its value, where 0 means verbose = no, 1 means verbose = yes

[AMDmi3]

en_US.ISO8859-1/books/porters-handbook/porting-dads/chapter.xml

349

MAKE_ARGS not ENV (based on my experience, only the former works)

I treat `MAKE_ARGS' as last resort for cases where variable is hard set in the upstream Makefile, while V is specially designed to be set from outside. So I think it should be MAKE_ENV by default, most ports which set V=1 use it already.

Clarify that it will only work for Makefiles that support or use the variable

IMO that'd be excessive. It already says it just a single possible tweak implying it only works and is needed for only some ports.

[koobs]

en_US.ISO8859-1/books/porters-handbook/porting-dads/chapter.xml

349

I treat MAKE_ARGS the same (last resort), but in my experience MAKE_ENV+=V=1 has worked less often than the former. That is the only reason I mentioned it as a comment here as information, not as a required change

It didn't read to me as V=1 works only for software that supports it, which is again why I mentioned it.

Both comments as feedback items only, not blocking commit. Your final call, but its perhaps worth getting someone on doc as a second opinion

[koobs]

Ping @wblock !

[wblock]

en_US.ISO8859-1/books/porters-handbook/porting-dads/chapter.xml

349

Given my trivial use of ports, V=1 looks like an arbitrary thing to me. If it has some special magic, that should be explained in at least some detail.

[mat]

I agree with @wblock, V=1 seems arbitrary, it should probably be in either a subsection or an example, explaining in which case it works.