title: how to choose libc6 or libc6-dbg
body: <p>Im bug checking a c program and would like to install valgrind, the system then tells me that I should also install libc6 with debug symbols libc6-dbg.</p>
  
  <p>Now my question is, when I in the future compile with gcc, which version of libc will be used?</p>
  
  <p>How do I choose which libc6 I'm compiling against?</p>
  
  <p>I'm not asking how to install this, I'm on ubuntu so apt-get install libc6-dbg will do the trick.</p>