title: cmake: problems specifying the compiler
body: <p>I have a problem with this CMakeLists.txt file:</p>
  
  <pre><code>cmake_minimum_required(VERSION 2.6)
  
  SET(CMAKE_C_COMPILER C:\\MinGW\\bin\\gcc)
  SET(CMAKE_CXX_COMPILER C:\\MinGW\\bin\\g++)
  
  project(cmake_test)
  
  add_executable(a.exe test.cpp)
  </code></pre>
  
  <p>Calling cmake with:  <code>cmake -G "MinGW Makefiles"</code></p>
  
  <p>I get:</p>
  
  <pre><code>c:\cmake_test&gt;cmake -G "MinGW Makefiles" .
  -- The C compiler identification is GNU 4.6.1
  CMake Warning (dev) at CMakeFiles/CMakeCCompiler.cmake:1 (SET):
    Syntax error in cmake code at
  
      C:/cmake_test/CMakeFiles/CMakeCCompiler.cmake:1
  
    when parsing string
  
      C:\MinGW\bin\gcc
  
    Invalid escape sequence \M
  
    Policy CMP0010 is not set: Bad variable reference syntax is an error.  Run
    "cmake --help-policy CMP0010" for policy details.  Use the cmake_policy
    command to set the policy and suppress this warning.
  Call Stack (most recent call first):
    CMakeLists.txt:12 (project)
  This warning is for project developers.  Use -Wno-dev to suppress it.
  
  -- The CXX compiler identification is GNU 4.6.1
  CMake Warning (dev) at CMakeFiles/CMakeCXXCompiler.cmake:1 (SET):
    Syntax error in cmake code at
  
      C:/cmake_test/CMakeFiles/CMakeCXXCompiler.cmake:1
  
    when parsing string
  
      C:\MinGW\bin\g++
  
    Invalid escape sequence \M
  
    Policy CMP0010 is not set: Bad variable reference syntax is an error.  Run
    "cmake --help-policy CMP0010" for policy details.  Use the cmake_policy
    command to set the policy and suppress this warning.
  Call Stack (most recent call first):
    CMakeLists.txt:12 (project)
  This warning is for project developers.  Use -Wno-dev to suppress it.
  
  -- Check for working C compiler: C:\MinGW\bin\gcc
  CMake Error at C:/cmake_test/CMakeFiles/CMakeCCompiler.cmake:1 (SET):
    Syntax error in cmake code at
  
      C:/cmake_test/CMakeFiles/CMakeCCompiler.cmake:1
  
    when parsing string
  
      C:\MinGW\bin\gcc
  
    Invalid escape sequence \M
  Call Stack (most recent call first):
    CMakeLists.txt:2 (PROJECT)
  
  CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage
  CMake Error: Internal CMake error, TryCompile configure of cmake failed
  CMake Error: your C compiler: "C:\MinGW\bin\gcc" was not found.   Please set CMAKE_C_COMPILER to a valid compiler path or name.
  CMake Error: your CXX compiler: "C:\MinGW\bin\g++" was not found.   Please set CMAKE_CXX_COMPILER to a valid compiler path or name.
  -- Configuring incomplete, errors occurred!
  </code></pre>
  
  <p>I also tried with:</p>
  
  <pre><code>C:\MinGW\bin\g++
  /C/MinGW/bin/g++
  </code></pre>
  
  <p>with the same result. Double quotes have not been helpful, either.</p>
  
  <p>Of course, the compiler is present in the specified directory.</p>
  
  <p>Thank you for any hint.</p>