[Buildroot] [PATCH 04/10] toolchain/external: add choice to select 'AT_LEAST_XXX' header version

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear Thomas De Schampheleire,

On Mon, 17 Feb 2014 09:07:29 +0100, Thomas De Schampheleire wrote:

> > I'm not sure I entirely grok your comment. This choice is only visible
> > for external toolchains, not for the internal backend, so there is not
> > two choices to set the kernel headers version.
> 
> True, but suppose the user did make the externel toolchain himself,
> for example with crosstool-ng. While creating the toolchain, he did
> get the question of which headers to use already, so he/she may think
> 'Huh? Why do I have to choose it again, and what will happen if I
> select a newer version here?"

This is something we already have for C++, large file, RPC, IPv6 and so
on. We have a typical help text for this:

          Select this option if your external toolchain has thread
          support. If you don't know, leave the default value,
          Buildroot will tell you if it's correct or not.

> Maybe you could also add that if the user is unsure about the exact
> version, it's 'safer' to specify an older version than a newer one.
> And maybe a way of determining the header version used in a toolchain,
> in case the user does not know it.

We should simply have a check that ensures the selection is correct.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com