Buildlink breakage with libstdc++.la

["Dr. Thomas Orgis" <thomas.orgis%uni-hamburg.de@localhost>]

I got a build error on a Linux box where I use the GCC in /usr. Trying
to build graphics/glu resulted in

sh-4.4$ make
  CXXLD    libGLU.la
/usr/bin/grep: /tmp/work-with-system-gcc/pkgsrc/2019Q1/pkgsrc-2019Q1/graphics/glu/work/.buildlink/lib/../lib/libstdc++.la: No such file or directory
/usr/bin/sed: can't read /tmp/work-with-system-gcc/pkgsrc/2019Q1/pkgsrc-2019Q1/graphics/glu/work/.buildlink/lib/../lib/libstdc++.la: No such file or directory
libtool:   error: '/tmp/work-with-system-gcc/pkgsrc/2019Q1/pkgsrc-2019Q1/graphics/glu/work/.buildlink/lib/../lib/libstdc++.la' is not a valid libtool archive
*** Error code 1

Stop.
make: stopped in /tmp/work-with-system-gcc/pkgsrc/2019Q1/pkgsrc-2019Q1/graphics/glu/work/glu-9.0.0


Now, there is this line in ../.buildlink/lib/libGL.la causing the issue:


dependency_libs='-lz /tmp/work-with-system-gcc/pkgsrc/2019Q1/pkgsrc-2019Q1/graphics/glu/work/.buildlink/lib/libglapi.la -lXext -lX11 -lxcb -lXau -lXdmcp -lXau -lXdmcp -lpthread -lrt -ldl
/tmp/work-with-system-gcc/pkgsrc/2019Q1/pkgsrc-2019Q1/graphics/glu/work/.buildlink/lib/../lib/libstdc++.la'

The libstdc++.la does indeed not exist. It was not created, but some
part of pkgsrc decided to mention it here.

When I replace that by -lstdc++ or just remove the entry (as CXXLD will
pull it in anyway … might be interesting for static libs used by a C
compiler, though, I guess), the build completes fine.

What is the actual bug here? Is the buildlink machinery supposed to
link in my libstdc++ from /usr? It does correctly reference and link
the libstdc++ on another box where I force pkgsrc to use a GCC prefix
of my own.


Alrighty then,

Thomas

-- 
Dr. Thomas Orgis
HPC @ Universität Hamburg