Using libsoc_gpio on the Beaglebone Black


Under examples_old/realtime in BeagleBone Debian, Cloud9 has sample C code called pushLED.c. This code includes libsoc_gpio.h and configures incoming and outgoing pins. It then sets a callback function so that changes on the incoming pin trigger the callback (like an interrupt service routine).
libsoc_gpio.h is not on the BeagleBone Black debian distribution, so I assume there is also a .lib that is also not there.

This seems like a super-useful feature. Anyone know why it is no longer available, and how to get it installed for use on the BBB?