Fix Object libraries cause problem on the mac build bot

[ImmanuelHaffner]

Collect all object files from the object libraries in a CMake variable using the $<TARGET_OBJECTS:objlib> syntax.
Use this variable when adding libbinaryen as static or shared library.
Using the object files in the add_library command should be most
portable.
Additionally, use the variable with the object files to simplify the
TARGET_LINK_LIBRARIES commands.

This fixes #2471.

[kripken]

Thanks @ImmanuelHaffner!

Testing locally, I see the same errors as on CI, No rule to make target [..] pass.cpp etc. Oddly, when I just run make again after that, it works...

[ImmanuelHaffner]

Oh damn. Could that mean that dependencies are missing...?

[kripken]

Doing some searching, I think the issue is that object libraries must be sources, not link flags, see

https://cmake.org/pipermail/cmake/2018-June/067721.html

With this patch I seem to get further, but hit another error, https://gist.github.com/kripken/56fbec00a34be9ed50522a0d5ddb298a

[kripken]

Oh, with that patch it looks like none of those libraries are linked in at all :( Anyhow, I'm not sure what's going on here, but that link does look relevant?

[ImmanuelHaffner]

Oh I see the problem. The binaryen_objs should be added to the add_executable and not target_link_libraries commands. As your source suggests, they must be listed as sources not linker arguments.
I will look into this tomorrow morning. It's just weird my system and my colleagues build the project just fine.

[kripken]

Yes, but that doesn't seem to work in my patch when I tried it... but maybe I did something wrong?

[kripken]

@ImmanuelHaffner

It looks like we don't have a fix for this today - I looked into a little more myself, but didn't figure it out. So I think we should revert the breaking PR. I'll wait a bit just in case you were about to update this PR, but otherwise will revert it. We can continue to figure out a proper fix after that.