[Buildroot] Why is libbsd limited to ARM, x86 and x86_64?

[Carlos Santos <casantos@datacom.ind.br>]

> From: "Arnout Vandecappelle" <arnout@mind.be>
> To: "Carlos Santos" <casantos@datacom.ind.br>, "buildroot" <buildroot@buildroot.org>
> Sent: Tuesday, February 2, 2016 7:09:28 PM
> Subject: Re: [Buildroot] Why is libbsd limited to ARM, x86 and x86_64?

> On 02-02-16 16:30, Carlos Santos wrote:
>> Hello,
>> 
>> I'm working on a project for PowerPC in which libbsd would be useful. However
>> the package is restricted to ARM, x86 and x86_64 architectures, since Config.in
>> contains this:
>> 
>>   # libbsd requires a.out.h, which is only available for those
>>   # architectures: arm, x86 (and alpha, currently not supported in Buildroot;
>>   # also m68k which is currently not enabled, so can't be tested.)
>>   default y if BR2_arm || BR2_i386 || BR2_x86_64
>> 
>> However, my PowerPC toolchain, generated by crosstool-NG, provides the required
>> a.out.h file. It is based on GCC 4.8.2, GLIBC 2.19 and Kernel 3.10.47.
>> 
>> Where does the information about the missing a.out.h on PowerPC comes from?
> 
> I had to do some archeology for this one :-)
> 
> This exclusion was from the time that we only supported glibc for external
> toolchains and it didn't get too much attention. So we missed the fact that
> glibc doesn't include linux/a.out.h so you won't get this[1] error. And it also
> seems that libbsd doesn't really require a.out support in the architecture (PPC
> doesn't support a.out), it just needs the a.out.h file to be present (in uClibc,
> a.out.h includes linux/a.out.h; in glibc, it doesn't). So for glibc, it works on
> any architecture.
> 
> Sometime later, the bump to 0.6.0 made libbsd require a glibc toolchain [2].
> But of course, nobody noticed that this meant that the architecture dependencies
> are no longer needed.
> 
> So it would be great if you could prepare a patch that removes the arch
> dependency and test if libbsd builds on all the arches that have glibc: aarch64,
> mips, sh, microblaze, sparc, nios2.
> 
> Regards,
> Arnout
> [1]
> http://autobuild.buildroot.org/results/019/019091312ec547520370ffad967b53e23f54a14b/
> [2]
> http://autobuild.buildroot.net/results/e94/e949d8fabeeecc74bd1c324c516e0b4938c99dbc/

OK, I will submit a patch.

Carlos Santos (Casantos)
DATACOM, P&D