Confirmation of commands plus unbreaking libpng

1. Libtool/GNU/free software is horrible and 100% broken forever.
   Libpng's configure basically ignores --with-zlib-prefix because they
   are free software and are 100% broken.  Without the correct
   corresponding -L, it doesn't work. Why?  Because GNU and "hey, let's
   be UNIX-y and support random directories EXCEPT LOLNO LET'S NOT
   SUPPORT ANYTHING THAT EVEN SLIGHTLY DEVIATES FROM THE DEFAULT
   DIRECTORIES GODDAMN THIS IS WHY TECHNOLOGY IS SO FUCKING TERRIBLE."