time.h: Add timeradd(), timersub(), timerclear(), timerisset(), and timercmp() as macros. These are non-POSIX interfaces, but included in most BSD deriviatives, included Linux.  From Manuel Stühn

waitpid:  CRITICAL BUGFIX.  Add a reference counting mechansim to prevent wait from using stale memory that was freed by the exiting task

Adds a driver for the PCA9635PW I2C LED driver IC which can be used to control the intensity of up to 16 LEDs.  From Alexander Entinger