Re: [PATCH] kbuild: simplify silent build (-s) detection

[Michal Marek]

On 2017-05-19 06:28, Masahiro Yamada wrote:
> This allows to detect -s option without checking GNU Make version.
> 
> As commit e36aaea28972 ("kbuild: Fix silent builds with make-4")
> pointed out, GNU Make 4.x changed the way/order it presents the
> command line options into MAKEFLAGS.
> 
> In Make 3.8x, 's' is always be the first in a group of short options.
> The group could be prefixed with '-'.
> 
> In Make 4.x, 's' is always the last in a group of short options.
> 
> As commit e6ac89fabd03 ("kbuild: Correctly deal with make options
> which contain an 's'") addressed, we also need to deal with long
> options that end with 's', like --warn-undefined-variables.
> 
> Test cases:
> 
> [1] command line input:    make --silent
>      -> MAKEFLAGS for Make 3.8x:    s
>      -> MAKEFLAGS for Make 4.x :    s
> 
> [2] command line input:    make -srR
>      -> MAKEFLAGS for Make 3.8x:    sRr
>      -> MAKEFLAGS for Make 4.x :    rRs
> 
> [3] command line input:    make -s -rR --warn-undefined-variables
>      -> MAKEFLAGS for Make 3.8x:    --warn-undefined-variables -sRr
>      -> MAKEFLAGS for Make 4.x :    rRs --warn-undefined-variables
> 
> We can take care of them, by filtering out long options (--%),
> then matching -s% s% %s patterns.

Good idea, that's a much cleaner way.

Michal