Needed header files and libraries are specified using the <header> and tags.

<header> just takes a filename as it would be used in an #include directive.

<lib> takes a library basename and the name of a function known to be in the library so that configure can test for it.

 <deps language="c" platform="unix">
  <header name="math.h"/>
  <lib    name="m" function="floor"/>
 </deps>