title: Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed
body: <p>When i use Cmake3.8.2 to compile OpenCV(the version of my visual studio is 2017),it always has errors  as follows:</p>
  
  <p><strong>Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed.
  Compiler:<br>
  Build flags: 
  Id flags:<br>
  The output was:
  The system cannot find the specified file .</strong></p>
  
  <p><strong>Compiling the C compiler identification source file "CMakeCCompilerId.c" failed.
  Compiler:<br>
  Build flags: 
  Id flags:<br>
  The output was:
  The system cannot find the specified file .</strong></p>
  
  <p>i've been confused for several days and it just doesn't work whatever i try.
  i'm looking for your help!</p>