title: CMake file command gives "Invalid escape sequence \." for regex rule
body: <p>I'm trying to do:</p>
  
  <pre><code>file(GLOB SOURCES "^[^.]+(?!\.in)\.c")
  </code></pre>
  
  <p>to match any file named <code>anything.c</code> but not the ones names <code>anything.in.c</code> but it gives me the error</p>
  
  <pre><code>Invalid escape sequence \.
  </code></pre>
  
  <p>I tried </p>
  
  <pre><code>file(GLOB SOURCES "*.c")
  list(REMOVE_ITEM SOURCES "*.in.c")
  </code></pre>
  
  <p>to not rely on regex but it looks like <code>list</code> command doesn't support regex like <code>file</code> does</p>