title: Do i need to install Command Line Tools for Xcode separately if i already have Xcode
body: <p>I tried to install gcc 5.2 (already installed dependencies successfully) from source file on my computer one week ago, but it failed at make phase or make install phase because of missing some ****.h files, whatever, i can not remember clearly. </p>
  
  <p>I searched the reason online, and looks like it is because i did not installed Command Line Tools for Xcode. But I already have Xcode 7.1.1 and i think it includes the Command Line Tool. I find it from File -> New -> project -> OS X Application -> Command Line Tool. I can also use gcc --version in the terminal.</p>
  
  <p>So do i need to install Command Line Tools separately? If I need, and why?</p>