build_sysimg (slightly) broken for Linux

[RalphAS]

With the official binary distributions for v0.7-alpha on Linux-x86_64 (two Linux distributions tried so far), I find that the build_sysimg script does not work; the symptom is that using the result gives:

$ /opt/julia7a/bin/julia -J /tmp/newsys.so
ERROR: System image file failed consistency check: maybe opened the wrong version?

The script itself appears to run happily:

INFO: cc -L/opt/julia-22590d529d/bin/../lib -shared -ljulia -o /tmp/newsys.so /tmp/newsys.o
┌ Warning: `info()` is deprecated, use `@info` instead.
│   caller = link_sysimg(::String, ::String, ::Bool) at build_sysimg.jl:178
└ @ Main build_sysimg.jl:178
INFO: System image successfully built at /tmp/newsys.so

But the resulting DLL is tiny. The trouble is that the object file newsys.o is an ar archive, which the linker searches but does not copy into the DLL.

I think the appropriate patch is to replace the link command so that it expands to

$ gcc -L/opt/julia-22590d529d/bin/../lib -shared -ljulia -o /tmp/newsys.so \
     -Wl,--whole-archive /tmp/newsys.o -Wl,--no-whole-archive

Alternatively, one could use ar to extract the actual object files and link them directly.

I encountered this problem while working around #26314.

[SimonDanisch]

related: #26672

[RalphAS]

Somehow I missed #27201 which this also duplicates. I can't say what would work on Windows or OSX.

In case it isn't clear from the above, after running the build_sysimg script (at least on Linux) one can copy the link command (which is conveniently echoed by the script), edit it as indicated above, and run it manually in a shell.

[SimonDanisch]

I think your issue is better ;) After all, you figured out the problem!