[Buildroot] luajit package fails to build on x86_64 for x86

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

Fabio, All,

On 2014-03-07 18:32 +0100, Fabio Porcedda spake thusly:
> On Fri, Mar 7, 2014 at 6:21 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote:
> > Fabio, All,
> >
> > On 2014-03-07 10:59 +0100, Fabio Porcedda spake thusly:
> >> On Thu, Mar 6, 2014 at 10:31 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote:
> >> > On 2014-03-06 11:43 +0100, Fabio Porcedda spake thusly:
> >> >> Hi all,
> >> >> luajit fails to build on a Ubuntu 13.10 x86_64 with the following defconfig:
> >> >>
> >> >> BR2_x86_generic=y
> >> >> BR2_TOOLCHAIN_EXTERNAL=y
> >> >> BR2_PACKAGE_LUAJIT=y
> > [--SNIP--]
> >> > And this can not work on a pure 64-bit system (aka, without the 32-bit
> >> > legacy stuff).
> > [--SNIP--]
> >> > Not sure how we can get away with this...
> >>
> >> I think we have two choices:
> >>  - add a check to test if 32bit compiler is installed and if not print
> >> a clear message about the toolchain requirement
> >
> > I think this would be the first package to add such a check.
> >
> > How would you propose we implement this:
> >   - in a pre-configure hook (but that will catch the failure late in the
> >     build) ?
> >   - in a make ifeq-block (so we can catch it early in the build) ?
> 
> > The second solution is more appealing to me, but might be a bit more
> > complex to implement.
> 
> I think a check to be added like this:
> 
> luakit.mk:
> 
> luajit-dependencies:
>    shell script to check and if it fails it prints an appropriate
> message and stop the building
> 
> dependencies: luajit-dependencies
> 
> So the check it's done early at same time as other dependenies check.

Doing the check in dependencies is not much better than doing it as a
pre-configure hook: it can be delayed quite late in the build process.

> Right now i don't know how to check about the presence of the 32bit
> support on the 64 bit host toolchain.

What about something like this:

    ifeq ($(BR2_PACKAGE_LUAJIT),y)
    ifeq ($(TARGET_32BIT)$(HOST_64BIT),yy)
    ifneq ($(shell echo 'int main() { return 0; }' |gcc -m32 -o foo -x c - >/dev/null 2>&1 && echo y; rm -f foo),y)
    $(error Can't build luajit for 32-bit target on this machine (mising 32-bit development packages))
    endif
    endif
    endif

Not really trivial, but should work with some tweaking...

Regards,
Yann E. MORIN.

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