[3/3] package/libarchive: fix linking issue with uClibc

With uClibc the dynamic linking loader functions needs
to be linked with -ldl

Fixes:
http://autobuild.buildroot.net/results/6af/6af140618b274536238b062635d493709905c8f6/build-end.log

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
---
 package/libarchive/libarchive.mk | 4 ++++
 1 file changed, 4 insertions(+)

Dear Romain Naour,

On Sun, 24 Aug 2014 18:53:06 +0200, Romain Naour wrote:
> With uClibc the dynamic linking loader functions needs
> to be linked with -ldl
> 
> Fixes:
> http://autobuild.buildroot.net/results/6af/6af140618b274536238b062635d493709905c8f6/build-end.log
> 
> Signed-off-by: Romain Naour <romain.naour@openwide.fr>
> ---
>  package/libarchive/libarchive.mk | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/package/libarchive/libarchive.mk b/package/libarchive/libarchive.mk
> index 8c6951d..ce3355c 100644
> --- a/package/libarchive/libarchive.mk
> +++ b/package/libarchive/libarchive.mk
> @@ -68,4 +68,8 @@ else
>  LIBARCHIVE_CONF_OPT += --without-zlib
>  endif
>  
> +ifeq ($(BR2_TOOLCHAIN_USES_UCLIBC),y)
> +LIBARCHIVE_CONF_ENV += LIBS="-ldl"
> +endif
> +
>  $(eval $(autotools-package))

I don't think this is the right fix, for several reasons:

 *) The problem only occurs due to the fact that bsdcpio and bsdtar are
    by default linked statically. When BR2_PREFER_STATIC_LIB is
    disabled, we should pass --enable-bsdtar=shared and
    --enable-bsdcpio=shared to ensure they are dynamically linked. This
    fixes the problem in the dynamic linking case.

 *) The problem is caused by the dependency of OpenSSL on libdl. So
    there is no need to always link against libdl: it should only be
    done when BR2_PREFER_STATIC_LIB=y and OpenSSL is enabled.

 *) I don't see why the problem would be uClibc specific.

Generally speaking, it's annoying to have to teach all packages
using OpenSSL that they should link against -ldl when doing static
linking. It would be so much better if everyone was using pkg-config...

Best regards,

Thomas

Hi Thomas,

Le 25/08/2014 23:03, Thomas Petazzoni a écrit :
> Dear Romain Naour,
> 
> On Sun, 24 Aug 2014 18:53:06 +0200, Romain Naour wrote:
>> With uClibc the dynamic linking loader functions needs
>> to be linked with -ldl
>>
>> Fixes:
>> http://autobuild.buildroot.net/results/6af/6af140618b274536238b062635d493709905c8f6/build-end.log
>>
>> Signed-off-by: Romain Naour <romain.naour@openwide.fr>
>> ---
>>  package/libarchive/libarchive.mk | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/package/libarchive/libarchive.mk b/package/libarchive/libarchive.mk
>> index 8c6951d..ce3355c 100644
>> --- a/package/libarchive/libarchive.mk
>> +++ b/package/libarchive/libarchive.mk
>> @@ -68,4 +68,8 @@ else
>>  LIBARCHIVE_CONF_OPT += --without-zlib
>>  endif
>>  
>> +ifeq ($(BR2_TOOLCHAIN_USES_UCLIBC),y)
>> +LIBARCHIVE_CONF_ENV += LIBS="-ldl"
>> +endif
>> +
>>  $(eval $(autotools-package))
> 
> I don't think this is the right fix, for several reasons:
> 
>  *) The problem only occurs due to the fact that bsdcpio and bsdtar are
>     by default linked statically. When BR2_PREFER_STATIC_LIB is
>     disabled, we should pass --enable-bsdtar=shared and
>     --enable-bsdcpio=shared to ensure they are dynamically linked. This
>     fixes the problem in the dynamic linking case.
> 
>  *) The problem is caused by the dependency of OpenSSL on libdl. So
>     there is no need to always link against libdl: it should only be
>     done when BR2_PREFER_STATIC_LIB=y and OpenSSL is enabled.
> 
>  *) I don't see why the problem would be uClibc specific.
> 
> Generally speaking, it's annoying to have to teach all packages
> using OpenSSL that they should link against -ldl when doing static
> linking. It would be so much better if everyone was using pkg-config...
> 

Ok, I misunderstood the problem, thanks for your explanations.
I'll try to fix this issue before the release.

Best regards,
Romain