[Buildroot] [UNSURE]Re: Some Perl modules fail to cross-compile

François Perrad francois.perrad at gadz.org
Thu Aug 14 19:03:39 UTC 2014

2014-08-14 11:22 GMT+02:00 Vicente Olivert Riera <Vincent.Riera at imgtec.com>:
> On 08/13/2014 05:50 PM, François Perrad wrote:
>> 2014-08-13 14:00 GMT+02:00 Vicente Olivert Riera
>> <Vincent.Riera at imgtec.com>:
>>> The affected modules are:
>>>   perl-gd
>>>   perl-net-ssleay
>>>   perl-xml-libxml
>>> The build system of these modules have a "use Config;" in the
>>> Makefile.PL.
>>> Given that we are cross-compiling, the Perl program used to run that
>>> Makefile.PL is the host's Perl program (because we can't run MIPS Perl in
>>> our x86_64 machine, for instance), so the %Config read only variable
>>> provided by the Config module contains all the information that the
>>> Configure program had during the Perl build time (in our case, the host's
>>> Perl). Then, the build system fills the OPTIMIZE variable (only if it's
>>> empty) with some flags taken from that %Config variable, so some things
>>> like
>>> "-mtune=generic" or "-m64" can end into the OPTIMIZE variable and cause a
>>> compilation failure for target architectures which don't support those
>>> flags.
>>> I have reported this bug upstream. Please read the comments:
>>>    https://rt.cpan.org/Public/Bug/Display.html?id=97834
>>> My proposal to fix these three packages is to append the OPTIMIZE
>>> variable
>>> to the configure options and set it to -mtune=$(BR2_GCC_TARGET_ARCH) to
>>> avoid the OPTIMIZE variable get filled with incompatible flags.
>>> I have the patches ready and they work, so, if you think this is a valid
>>> solution, just tell it to me and I will send the patches ASAP.
>> The host perl must load the host Config.pm.
>> So, in order to cross compiling, we must overload all variables in the
>> command line.
>> Currently, only CCFLAGS/ccflags is set in package/pkg-perl.mk, in the same
>> way,
>> we could also set OPTIMIZE with " ".
> I don't mind if we fix this by patching the .mk files of the three affected
> packages, or by patching the BR perl-package build system.

Perl module packages are not hand written, like other packages, but there are
generated by support/script/scancpan.


> In case if we adopt the second solution (yours), don't you think it's better
> to set the OPTIMIZE variable to "-mtune=$(BR2_GCC_TARGET_ARCH)" instead of
> just " "?
>> François
>>> Thanks.
>>> --
>>> Vincent
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> --
> Vincent

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