[Buildroot] [PATCH v2 2/2] Makefile: pass host PKG_CONFIG_PATH at "make menuconfig" time

[Bjørn Forsman]

On 2 January 2015 at 22:28, Bjørn Forsman <bjorn.forsman at gmail.com> wrote:
> Hi Yann,
>
> Thanks for the feedback. Comments below.
>
> On 2 January 2015 at 17:16, Yann E. MORIN <yann.morin.1998 at free.fr> wrote:
>> Bjørn, All,
>>
>> On 2015-01-01 21:54 +0100, Bjørn Forsman spake thusly:
>>> Buildroot unexports PKG_CONFIG_PATH in the top-level Makefile for purity
>>> reasons. But it has an unfortunate side-effect in that "make menuconfig"
>>> will not (necessarily) be able to pick up ncurses via host pkg-config,
>>> breaking "make menuconfig" on systems where ncurses is installed in a
>>> non-standard location.
>>>
>>> This patch saves the original PKG_CONFIG_PATH variable in
>>> HOST_PKG_CONFIG_PATH and restores the original PKG_CONFIG_PATH variable
>>> only in the sub-processes that builds the various menuconfig/nconfig/...
>>> targets.
>>>
>>> With this change, I am able to run "make menuconfig" on NixOS[1].
>>>
>>> [1]: http://nixos.org/
>>>
>>> Signed-off-by: Bjørn Forsman <bjorn.forsman at gmail.com>
>>> ---
>>>  Makefile | 6 +++++-
>>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Makefile b/Makefile
>>> index 5e0b4f2..2f1108f 100644
>>> --- a/Makefile
>>> +++ b/Makefile
>>> @@ -264,6 +264,7 @@ export HOSTAR HOSTAS HOSTCC HOSTCXX HOSTFC HOSTLD
>>>  export HOSTCC_NOCCACHE HOSTCXX_NOCCACHE
>>>
>>>  # Make sure pkg-config doesn't look outside the buildroot tree
>>> +export HOST_PKG_CONFIG_PATH=$(PKG_CONFIG_PATH)
>>
>> I think you'd want to do an immediate assignment here, and not do an
>> export (see below):
>>
>>     HOST_PKG_CONFIG_PATH:=$(PKG_CONFIG_PATH)
>
> Will fix.

Some comments. There are other HOST_* variables that are exported from
the top-level Makefile. I guess that's why I used 'export' in the
first place. For now, nobody but Buildroot itself uses
HOST_PKG_CONFIG_PATH (well, when this patch gets in), but I can see a
future where pkg-config is used within Buildroot for other host
packages too. But it is of course trivial to add the "export" at any
time :-)

- Bjørn