CMake configures wrong for Clang

[stevenrbrandt]

Expected Behavior

on docker image stevenrbrandt/clangmi

git clone https://github.com/STEllAR-GROUP/parallelnumericalintegration.git
mkdir parallelnumericalintegration/build
cd parallelnumericalintegration/build
cmake -DCMAKE_CXX_COMPILER=$(which clang++) ..

fails with

[ 10%] Building CXX object src/CMakeFiles/taylor_par_hpx.dir/taylor_par_hpx.cpp.o
[ 20%] Linking CXX executable taylor_par_hpx
/usr/bin/ld: /usr/local/lib64/libhpx_wrap.a(hpx_wrap.cpp.o): undefined reference to symbol '_ZNKSt3__114error_category10equivalentEiRKNS_15error_conditionE'
/usr/bin/ld: /usr/lib64/libc++.so.1: error adding symbols: DSO missing from command line
clang-14: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [src/CMakeFiles/taylor_par_hpx.dir/build.make:103: src/taylor_par_hpx] Error 1
make[1]: *** [CMakeFiles/Makefile2:862: src/CMakeFiles/taylor_par_hpx.dir/all] Error 2
make: *** [Makefile:146: all] Error 2

You can fix the problem by configuring as follows:

cmake -DCMAKE_CXX_COMPILER=$(which clang++) -DCMAKE_CXX_FLAGS=-stdlib=libc++ ..

Specifications

... Please describe your environment
Docker image: stevenrbrandt/clangmi

• HPX Version: 1.8.1
• Platform (compiler, OS):
  $ uname -a
  Linux 49a6c2f51cac 5.10.102.1-microsoft-standard-WSL2 Full path specified in CTest #1 SMP Wed Mar 2 00:30:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

[stevenrbrandt]

Here's how I configured HPX

cmake \
    -DHPX_WITH_EXAMPLES=OFF \
    -DHPX_WITH_MORE_THAN_64_THREADS=ON \
    -DCMAKE_CXX_COMPILER=clang++ \
    -DHPX_WITH_CXX_STANDARD=20 \
    -DCMAKE_CXX_FLAGS=-stdlib=libc++ \
    -DHPX_WITH_FETCH_ASIO=ON \
    ..

[hkaiser]

You used -DCMAKE_CXX_FLAGS=-stdlib=libc++ while configuring HPX, I'd expect you need to do the same for all depending projects.

[stevenrbrandt]

So the question is, why doesn't cmake pass the flags along? The hpxcxx command does. Shouldn't they both do it?