title: Missing C & C++ compilers in Windows Subsystem for Linux
body: <p>I'm trying to compile LLVM using the Windows Subsystem for Linux (Windows 10 build 10.0.14342), but I keep getting cmake errors about how I'm missing C &amp; C++ compilers. This is despite having gcc, g++, and build-essentials by using apt-get from within bash. My command is as follows: </p>
  
  <pre><code>cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD="X86" ../llvm-3.8
  </code></pre>
  
  <p>I get a bunch of errors from CMake</p>
  
  <pre>
  CMake Error: Parse error in cache file /home/andrew-wsl/llvm/build/CMakeCache.txt. 
  Offending entry: Debug Info builds.
  CMake Error: Parse error in cache file /home/andrew-wsl/llvm/build/CMakeCache.txt. 
  Offending entry: CMAKE_MODULE_LINKER_FLAGS_RELEASE-ADVANCED
  -- The C compiler identification is unknown
  CMake Error at /usr/share/cmake-2.8/Modules/CMakeDetermineCCompiler.cmake:186 (configure_file):
    configure_file Problem configuring file
  Call Stack (most recent call first):
    CMakeLists.txt:54 (project)
  
  
  -- The CXX compiler identification is unknown
  CMake Error at /usr/share/cmake-2.8/Modules/CMakeDetermineCXXCompiler.cmake:185 (configure_file):
    configure_file Problem configuring file
  Call Stack (most recent call first):
    CMakeLists.txt:54 (project)
  
  
  -- The ASM compiler identification is GNU
  -- Found assembler: /usr/bin/cc
  -- Check for working C compiler: /usr/bin/cc
  CMake Error at /usr/share/cmake-2.8/Modules/CMakeTestCCompiler.cmake:47 (try_compile):
    Unknown extension ".c" for file
  
      /home/andrew-wsl/llvm/build/CMakeFiles/CMakeTmp/testCCompiler.c
  
    try_compile() works only for enabled languages.  Currently these are:
  
      ASM C CXX
  
    See project() command to enable other languages.
  Call Stack (most recent call first):
    CMakeLists.txt:54 (project)
  
  
  -- Check for working C compiler: /usr/bin/cc -- broken
  CMake Error at /usr/share/cmake-2.8/Modules/CMakeTestCCompiler.cmake:61 (message):
    The C compiler "/usr/bin/cc" is not able to compile a simple test program.
  
    It fails with the following output:
  
  
  
  
  
    CMake will not be able to correctly generate this project.
  Call Stack (most recent call first):
    CMakeLists.txt:54 (project)
  
  
  -- Configuring incomplete, errors occurred!
  See also "/home/andrew-wsl/llvm/build/CMakeFiles/CMakeOutput.log".
  See also "/home/andrew-wsl/llvm/build/CMakeFiles/CMakeError.log".
  andrew-wsl@COMPUTER:~/llvm/build$
  </pre>
  
  <p>CMakeError.log can be found here: <a href="http://pastebin.com/7rWYFGu5" rel="nofollow">http://pastebin.com/7rWYFGu5</a></p>
  
  <p>CMakeOutput.log can be found here: <a href="http://pastebin.com/2BaEFTvR" rel="nofollow">http://pastebin.com/2BaEFTvR</a></p>
  
  <p>I'm not sure what's going on as I was able to compile a helloworld program with gcc and g++ successfully.</p>