-- The C compiler identification is unknown
-- The CXX compiler identification is unknown
-- The ASM compiler identification is unknown
-- Found assembler: /usr/bin/clang
-- Check for working C compiler: /usr/bin/clang
-- Check for working C compiler: /usr/bin/clang -- broken
CMake Error at /usr/share/cmake-3.7/Modules/CMakeTestCCompiler.cmake:51 (message):
  The C compiler "/usr/bin/clang" is not able to compile a simple test
  program.

  It fails with the following output:

   Change Dir: /var/makepkg/libc++/src/build/CMakeFiles/CMakeTmp



  Run Build Command:"/usr/bin/make" "cmTC_46112/fast"

  /usr/bin/make -f CMakeFiles/cmTC_46112.dir/build.make
  CMakeFiles/cmTC_46112.dir/build

  make[1]: Entering directory
  '/var/makepkg/libc++/src/build/CMakeFiles/CMakeTmp'

  Building C object CMakeFiles/cmTC_46112.dir/testCCompiler.c.o

  /usr/bin/clang -march=x86-64 -mtune=generic -O2 -pipe
  -fstack-protector-strong -g -fvar-tracking-assignments -o
  CMakeFiles/cmTC_46112.dir/testCCompiler.c.o -c
  /var/makepkg/libc++/src/build/CMakeFiles/CMakeTmp/testCCompiler.c

  clang-3.9: error: unknown argument: '-fvar-tracking-assignments'

  make[1]: *** [CMakeFiles/cmTC_46112.dir/build.make:66:
  CMakeFiles/cmTC_46112.dir/testCCompiler.c.o] Error 1

  make[1]: Leaving directory
  '/var/makepkg/libc++/src/build/CMakeFiles/CMakeTmp'

  make: *** [Makefile:126: cmTC_46112/fast] Error 2





  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:48 (project)


-- Configuring incomplete, errors occurred!
See also "/var/makepkg/libc++/src/build/CMakeFiles/CMakeOutput.log".
See also "/var/makepkg/libc++/src/build/CMakeFiles/CMakeError.log".