title: GCC doesn't produce line number information even with -g option
body: <p>I have built and installed GCC 4.8.1 from source:</p>
  
  
  
  <pre class="lang-none prettyprint-override"><code>$ gcc -v
  Using built-in specs.
  COLLECT_GCC=gcc
  COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.8.1/lto-wrapper
  Target: x86_64-unknown-linux-gnu
  Configured with: ./configure --disable-multilib
  Thread model: posix
  gcc version 4.8.1 (GCC) 
  </code></pre>
  
  <p>And I've written a simple useless program:</p>
  
  <pre class="lang-c prettyprint-override"><code>$ cat hw.c
  #include &lt;stdio.h&gt;
  
  void foo()
  {
      int a;
      scanf("%d", &amp;a); /* So I can press ctrl+c here. */
      printf("Hello world!\n");
  }
  
  int main()
  {
      foo();   
  }
  </code></pre>
  
  <p>Now I compile this:</p>
  
  <pre class="lang-none prettyprint-override"><code>$ gcc -g -O0 hw.c -o hw
  </code></pre>
  
  <p>Then started debugging it with GDB:</p>
  
  <pre class="lang-none prettyprint-override"><code>$ gdb hw
  GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04
  Copyright (C) 2012 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later &lt;http://gnu.org/licenses/gpl.html&gt;
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
  and "show warranty" for details.
  This GDB was configured as "x86_64-linux-gnu".
  For bug reporting instructions, please see:
  &lt;http://bugs.launchpad.net/gdb-linaro/&gt;...
  Reading symbols from /home/calmarius/workdir/crucible/hw/hw...done.
  (gdb) 
  </code></pre>
  
  <p>Run it and Ctrl+C it immediately:</p>
  
  <pre class="lang-none prettyprint-override"><code>(gdb) run
  Starting program: /home/dcsirmaz/workdir/crucible/hw/hw 
  ^C
  Program received signal SIGINT, Interrupt.
  0x00007ffff7b018b0 in __read_nocancel () at ../sysdeps/unix/syscall-template.S:82
  82  ../sysdeps/unix/syscall-template.S: Nincs ilyen fájl vagy könyvtár.
  </code></pre>
  
  <p>I got function names in the backtrace but no line numbers in my code:</p>
  
  <pre class="lang-none prettyprint-override"><code>(gdb) bt
  #0  0x00007ffff7b018b0 in __read_nocancel () at ../sysdeps/unix/syscall-template.S:82
  #1  0x00007ffff7a95ff8 in _IO_new_file_underflow (fp=0x7ffff7dd4340) at fileops.c:619
  #2  0x00007ffff7a9703e in _IO_default_uflow (fp=0x7ffff7dd4340) at genops.c:440
  #3  0x00007ffff7a74fb6 in _IO_vfscanf_internal (s=&lt;optimized out&gt;, format=&lt;optimized out&gt;, argptr=0x7fffffffe018, errp=0x0) at vfscanf.c:620
  #4  0x00007ffff7a790bd in __isoc99_scanf (format=&lt;optimized out&gt;) at isoc99_scanf.c:37
  #5  0x000000000040054e in foo ()
  #6  0x0000000000400568 in main ()
  </code></pre>
  
  <p>What's gone wrong? Maybe is it something with the configuration?</p>