[Buildroot] FW: [PATCH] external toolchain: use relative path to external toolchain.

[Yann E. MORIN <yann.morin.1998@free.fr>]

Noam, All,

On 2014-02-23 08:29 +0000, Noam Camus spake thusly:
> Now configuration may include relative path to external toolchain.

What is the use-case for providing a relative path?

Do not forget that relative paths are always relative to the top dir of
the Buildroot source tree, not the current directory.

For example, if you build out-of-tree, then the relative paths are still
relative to Buildroot's tree, not $(O), which can have some strange
consequences:

    # ls -lF
    buildroot/
    ext-toolchain/
    $ mkdir -p my/own/output/dir
    $ cd my/own/output/dir
    $ make -C ../../../../buildroot O=$(pwd) my_defconfig all

So, you would have to set BR2_TOOLCHAIN_EXTERNAL_PATH=../ext-toolchain,
which is not straightforward, as most users would expect to set a path
relative to the current working directory. [0]

But, if you want to use relative paths, you can do use $(TOPDIR) or
$(CONFIG_DIR) as a prefix.

So, I'm not really sure we want that.

[0] This is not Buildroot's fault, but a standard behaviour of make,
that prevents us from knowing the directory make was run from in the
first place. This information is lost, and can not be retrieved from
inside a Makefile.

Regards,
Yann E. MORIN.

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