[Buildroot] [PATCH 2/3 v3] linux: kconfig needs host-{flex, bison} to build the configurators

[Arnout Vandecappelle]

On 15/08/2018 14:18, Thomas Petazzoni wrote:
> Hello,
> 
> On Wed, 15 Aug 2018 00:50:42 +0200, Arnout Vandecappelle wrote:
[snip]
> I'd prefer to see:
> 
>   LINUX_KCONFIG_DEPENDENCIES = $(BR2_FLEX_HOST_DEPENDENCY) $(BR2_BISON_HOST_DEPENDENCY)
> 
> And the usual logic in support/dependencies/ to check for bison/flex.
> This will avoid disrupting all existing setups, and still provide the
> speed-up that we don't need to build flex/bison when doing "make
> linux-menuconfig".

 +1. It also makes it easy to add the feature "build flex is system version is
not OK" later.


>>> For the linux kernel and other kconfig-based packages, we don't care
>>> which flex/bison are used, because the resulting binaries are not
>>> installed, unless those packages also generate code eventually installed
>>> in host/, staging/ or target/  
>>
>>  Note that this means you'll still need host-flex/bison for the kernel, because
>> the kernel may build dtc and that gets installed in host...
> 
> Are you sure flex/bison are used when building the DTC copy in the
> Linux kernel ? Indeed we only added host-bison/host-flex as
> dependencies of linux in commit
> 1b9faedf32be26d9c983c573ccd98f57fc6f6569, when kconfig stopped shipping
> its pre-generated files. How could DTC be built before
> 1b9faedf32be26d9c983c573ccd98f57fc6f6569 if it required bison/flex ?

 The shipped files for DTC were removed in
e039139be8c25145b103ab365ff1bd4a540066a3 which is v4.17-rc1~106^2~8^2~2 (while
the kconfig stuff was removed in 29c833061c1d8c2d1d23a62e7061561eadd76cdb which
is v4.16-rc1~105^2~26). So we already had the dependencies when the shipped DTC
files were removed from the kernel. And as Yann said, they're not needed for
kconfig itself, only for building.

 Regards,
 Arnout

> 
> Best regards,
> 
> Thomas
> 

-- 
Arnout Vandecappelle                          arnout at mind be
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