BSD build fail

Ahoy,

I am trying to build the git repo version of SDL on ghostBSD, but it fails to finish compiling and throws this error:

/usr/home/../Desktop/SDL_port/lib/SDL/src/core/linux/SDL_evdev_capabilities.h:30:10: fatal error: 'linux/input.h' file not found
#include <linux/input.h>
         ^~~~~~~~~~~~~~~

I’ve used GCC 11 to compile FYI.
Any ideas what is going on?