title: libpng "png_set_longjmp_fn" not found
body: <p>I'm using libpng from ubuntu and when I try to compile a c++ file I get</p>
  
  <p>undefined reference to `png_set_longjmp_fn'</p>
  
  <p>I'm using libpng version 1.6.8</p>
  
  <p>If you are interested in reading the code please let me know, but I do not this has to do with my bad code.</p>
  
  <p>Thank you in advance.</p>