Build failure on Fedora 29

[nitronoid]

Describe the bug
Getting the same error output as #16 with an up to date clone of master.

To Reproduce
I'm using this CMAKE command:

> CC=/usr/bin/clang CXX=/usr/bin/clang++ CXXFLAGS=-stdlib=libc++ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DFILAMENT_REQUIRES_CXXABI=true -DCMAKE_INSTALL_PREFIX=../release/filament ../..
> ninja

Same story with regular make files. As you can see I do have the CXXABI flag.

Desktop (please complete the following information):

• OS: Fedora 29
• GPU: NVIDIA Quadro M3000M

Additional context
I was able to fix this problem by modifying the main CMakeLists.txt to link libc++, apparently it wasn't doing this? I added link_libraries(libc++.a) and now it builds fine. Maybe there's a better fix.

[romainguy]

We link against libc++ via this flag: set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++") which works on other Linux distributions (and macOS and Android). I'm not sure why an extra link_libraries() directive is required here.

[nitronoid]

I think the problem is that -stdlib=libc++ is not visible to the linker, instead of adding link_libraries(libc++.a) I can alternatively use

set(CMAKE_LINK_FLAGS "${CMAKE_LINK_FLAGS} -stdlib=libc++")

which also fixes the problem.

[romainguy]

Ah good point, I'll give it a try, thanks!

[nitronoid]

Just an update on this, the second solution I posted only works when compiling for debug, to build the release version I still require the link_libraries(libc++.a). I noticed the conditional linking against static-libc++ for release mode, does adding the extra link_libraries have any negative effects?

[romainguy]

It should be fine but this link_libraries should be done implicitly by -static-libstdc++, and it's what happens when we build on Debian. What version of Clang are you using btw?

[nitronoid]

I'm using clang 7.0.1 with Fedora 29, I also tested with clang 9.0.0 on a rhel-7 workstation.

[romainguy]

Would you mind trying #1245 please? It works on my Debian (custom Google) and our CI (Ubuntu 14). This change always links statically against libc++ and libc++abi, in debug and release.

[nitronoid]

Sure I'll try it now

[nitronoid]

Works for me! Don't need to put any special flags either which is nice 👍

CC=/usr/bin/clang CXX=/usr/bin/clang++ cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=../release/filament ../..

[romainguy]

Awesome, thank you so much for your help! I really appreciate it.