[PATCH -next 2/2] kbuild: fix for updated LZ4 tool with the new streaming format

[mingo@kernel.org (Ingo Molnar)]

* Kyungsik Lee <kyungsik.lee@lge.com> wrote:

> LZ4 has been updated with LZ4 Streaming Format specification(v1.3).
> lz4demo is replaced by lz4c. lz4c supports both the new streaming and
> legacy format with -l option.
> 
> This patch makes use of lz4c to support legacy format which is
> used for LZ4 De/compression in the linux kernel.
> 
> Link: https://code.google.com/p/lz4/source/checkout
> Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Russell King <rmk@arm.linux.org.uk>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Florian Fainelli <florian@openwrt.org>
> Cc: Yann Collet <yann.collet.73@gmail.com>
> Cc: Chanho Min <chanho.min@lge.com>
> ---
>  scripts/Makefile.lib | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index a0ab6d7..c9bfbb0 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -313,7 +313,7 @@ cmd_lzo = (cat $(filter-out FORCE,$^) | \
>  
>  quiet_cmd_lz4 = LZ4     $@
>  cmd_lz4 = (cat $(filter-out FORCE,$^) | \
> -	lz4demo -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
> +	lz4c -l -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
>  	(rm -f $@ ; false)

None of the major distros I tried has the lz4 or lz4c binary available, 
and this breaks randconfig builds:

  /bin/sh: lz4c: command not found

If:

 CONFIG_HAVE_KERNEL_LZ4=y
 CONFIG_KERNEL_LZ4=y
 CONFIG_RD_LZ4=y
 CONFIG_LZ4_DECOMPRESS=y
 CONFIG_DECOMPRESS_LZ4=y

If a utility is not widely available yet and if the utility is not in the 
kernel proper, could you please at least make sure that randconfig does 
not stumble over non-buildable kernels?

Thanks,

	Ingo