cmake fails to generate makefiles #478
Description
Running this command on some Ubuntu systems:
cmake -G"Unix Makefiles" -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=RelWithDebInfo -B. ../CMake
(from README.md "Linux --- Clang" instructions)
Gives the following error message:
"/usr/bin/clang++"
is not able to compile a simple test program.
It fails with the following output:
Change Dir: /mnt/ssd3/workspace/github/iam/rxcpp/projects/build/CMakeFiles/CMakeTmp
Run Build Command:"/usr/bin/make" "cmTC_861e7/fast"
/usr/bin/make -f CMakeFiles/cmTC_861e7.dir/build.make CMakeFiles/cmTC_861e7.dir/build
make[1]: Entering directory '/mnt/ssd3/workspace/github/iam/rxcpp/projects/build/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_861e7.dir/testCXXCompiler.cxx.o
/usr/bin/clang++ -o CMakeFiles/cmTC_861e7.dir/testCXXCompiler.cxx.o -c /mnt/ssd3/workspace/github/iam/rxcpp/projects/build/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
Linking CXX executable cmTC_861e7
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_861e7.dir/link.txt --verbose=1
/usr/bin/clang++ -rdynamic CMakeFiles/cmTC_861e7.dir/testCXXCompiler.cxx.o -o cmTC_861e7
/usr/bin/ld: cannot find -lstdc++
clang: error: linker command failed with exit code 1 (use -v to see invocation)
CMakeFiles/cmTC_861e7.dir/build.make:97: recipe for target 'cmTC_861e7' failed
make[1]: *** [cmTC_861e7] Error 1
make[1]: Leaving directory '/mnt/ssd3/workspace/github/iam/rxcpp/projects/build/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_861e7/fast' failed
make: *** [cmTC_861e7/fast] Error 2
The fix appears to be to append -DCMAKE_EXE_LINKER_FLAGS="-stdlib=libc++" to the above cmake command line.
Interestingly enough, projects/CMake/shared.cmake already adds that flag, but it seems that the file is included too late for the test cmake program to succeed.