[Buildroot] [PATCH v2] Makefile: remove extra ifdef/endif of top Makefile
Yann E. MORIN
yann.morin.1998 at free.fr
Tue Apr 7 17:13:31 UTC 2015
Masahiro, All,
On 2015-04-07 14:09 +0900, Masahiro Yamada spake thusly:
> The GNU make's origin function know undefined variable well,
> so the outer ifdef/endif conditional checking is unneeded.
>
> From `info make` documentation, origin will return
>
> `undefined'
> if VARIABLE was never defined.
> `command line'
> if VARIABLE was defined on the command line.
> ...
>
> Therefore, $(origin V) will get a value anyway, killing ifdef/endif
> is viable and safe.
>
> Furthermore, I've checked the minimal requirements from the top
> Makefile is GNU make 3.81, and that version of GNU make has support
> of origin function well already, so now it's safe to kill the outer
> conditional checking, without upgrading the minimal requirements.
>
> Signed-off-by: Cheng Renquan <crq at kernel.org>
> Signed-off-by: Sam Ravnborg <sam at ravnborg.org>
> [ Commit description is borrowed from Linux Kernel
> (commit b8b0618cf6fa) and adjusted for Buildroot ]
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Regards,
Yann E. MORIN.
> ---
>
> Changes in v2:
> - Add more detailed explanation
>
> Makefile | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index d6426b3..9db52a8 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -184,10 +184,8 @@ endif
>
> # To put more focus on warnings, be less verbose as default
> # Use 'make V=1' to see the full commands
> -ifdef V
> - ifeq ("$(origin V)", "command line")
> - KBUILD_VERBOSE = $(V)
> - endif
> +ifeq ("$(origin V)", "command line")
> + KBUILD_VERBOSE = $(V)
> endif
> ifndef KBUILD_VERBOSE
> KBUILD_VERBOSE = 0
> --
> 1.9.1
>
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot
--
.-----------------.--------------------.------------------.--------------------.
| Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software Designer | \ / CAMPAIGN | ___ |
| +33 223 225 172 `------------.-------: X AGAINST | \e/ There is no |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL | v conspiracy. |
'------------------------------^-------^------------------^--------------------'
More information about the buildroot
mailing list