$(ISYSTEM) considered harmful

[Stephan Bergmann]

On 04/01/2013 01:04 PM, Michael Stahl wrote:
> On 31/03/13 14:52, Tor Lillqvist wrote:
>> make clean helps. (if you have the patience, you can do "make
>> foo.clean" for each module that depend on icu.)
>
> if "make clean" helps, most likely something is clearly wrong.
> in this case apparently the following commit broke incremental builds of
> external libraries:
>
> commit 151abb8b2b9d3a22229b98cec12e29484d12109b
> Author: Luboš Luňák <l.lunak at suse.cz>
> Date:   Tue Mar 19 16:39:49 2013 +0100
>
>      use -isystem instead of -I for 3rd party headers
>
>      This should avoid gcc warnings in external code we don't care about,
>      so there'll be no need to fix them for WaE.
>
> well it's true you don't get warnings when you use -isystem; you also
> don't get makefile dependencies generated :(

Though in this case with icu 49 vs. 51, at least what broke the 
incremental build for me was that old icu headers still lay around in 
solver/*/inc/external/ (and got picked up from there in dependent 
modules) from a time when icu headers got delivered to solver instead of 
being used directly from workdir/*/UnpackedTarball/icu/...

Stephan