[Buildroot] [PATCH 1/5] core/pkg-cmake: provide our own platform description

["Jörg Krause" <joerg.krause@embedded.rocks>]

Hi Yann,

On Tue, 2017-02-28 at 21:58 +0100, Yann E. MORIN wrote:
> J?rg, All,
> 
> On 2017-02-28 21:41 +0100, J?rg Krause spake thusly:
> > On Tue, 2017-02-28 at 19:07 +0100, Yann E. MORIN wrote:
> > > The handling of RPATH in cmake-3.7 has changed drastically,
> > > causing a
> > > slew of build failures dues to libraries from the host being
> > > pulled
> > > in:
> > > 
> > > ? - domoticz : http://autobuild.buildroot.org/results/fd0/fd0ba54
> > > c7ab
> > > f973691b39a0ca1bb4e07d749593a/
> > > ? - freerdp??: http://autobuild.buildroot.org/results/5d4/5d429d0
> > > e288
> > > 754a541ee5d8be515454c5fccd28b/
> > > ? - libcec???: http://autobuild.buildroot.org/results/3f3/3f3593b
> > > ab77
> > > 34dd274faf5b5690895e9424cbb89/
> > > ? - and so on...
> > > 
> > > The bug was reported upstream [0], which dismissed it altogether
> > > [1]
> > > as
> > > being expected behaviour, quoting:
> > > 
> > > ????I don't think there is anything wrong with that change on its
> > > own.
> > > ????It merely exposed some existing behavior in a new case.
> > > 
> > > Instead, upstream suggested in that same message that a platform
> > > definition be used instead, quoting:
> > > 
> > > ????If a toolchain file specifies CMAKE_SYSTEM_NAME such that a
> > > custom
> > > ????`Platform/MySystem.cmake` file is loaded then the latter can
> > > set
> > > ????them as needed for the target platform.
> > 
> > Upstream has opened an issue [1] about this and is already working
> > on a
> > fix [2] for version 3.7 and 3.8. It fixes the behavior of how
> > FIND_LIBRARY_USE_LIB32_PATHS handle symlinks.?As 'lib32' is just
> > just a
> > symlink to 'lib' in Buildroot, 'find_library()' will skip 'lib32'
> > as a
> > runtime search path and as a consequence 'lib32' will not be used
> > as
> > rpath anymore.
> > 
> > > So here we are doing so:
> > > 
> > > ? - we add a new platfom definitions that inherits from the Linux
> > > one,
> > > ????then overrides the problematic settings;
> > > 
> > > ? - we change our toolchain file to use that platform instead;
> > > 
> > > ? - we tell cmake where to find additional modules, so that it
> > > can
> > > find
> > > ????our custom platform file.
> > 
> > As the issue might be fixed at some point, do we want to keep the
> > custom platform file?
> 
> Well, what bad would it do to have our own platform file? We could
> even
> use it for yet more options if need be.

No offense. There is nothing wrong about having a custom buildroot
platform file.

> And in the meantime, there is no release of cmake with a fix. I'll
> believe they've fixed it when I see it! ;-)

:-)

J?rg