[Buildroot] Adding package libgit2

[Thomas Petazzoni]

Hello,

On Wed, 14 Feb 2018 16:30:24 +0100, Nicolas Cavallari wrote:

> > ARCH is set to ${CMAKE_SYSTEM_PROCESSOR}, and CMAKE_SYSTEM_PROCESSOR is
> > explicitly passed by Buildroot in package/pkg-cmake.mk. So it should be
> > correct. zlib-ng CMakeLists.txt uses its ${ARCH} variable to decide
> > whether the x86 code should be built or not:
> > 
> > if("${ARCH}" MATCHES "x86_64" OR "${ARCH}" MATCHES "AMD64")
> >     set(ARCHDIR "arch/x86")
> >     add_definitions(-DX86_64 -DX86_NOCHECK_SSE2 -DUNALIGNED_OK -DUNROLL_LESS)
> >     add_feature_info(SSE2 1 "Use the SSE2 instruction set, using \"${SSE2FLAG}\"")  
> 
> I have added --trace to cmake.  There is this gem a few lines below:
> 
> else()
>     set(ARCHDIR "arch/x86")
>     add_definitions(-DX86 -DUNALIGNED_OK -DUNROLL_LESS)
>     add_feature_info(SSE2 1 "Support the SSE2 instruction set, using
> \"${SSE2FLAG}\"")
> endif()
> 
> So anything not arm/aarch64/x86 is treated like x86 anyway...

Which obviously is not going to work very well :)

I guess this should be fixed and/or reported to zlib-ng upstream. In
the mean time, either we fix it, or we disallow zlib-ng on
architectures other than arm/aarch64/x86.

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com