Merge remote-tracking branch 'qatar/master'

* qatar/master:
  file: Only include unistd.h if it exists
  random_seed: Only read /dev/*random if we have unistd.h
  doc: Indicate that RTMPT is natively implemented in libavformat
  rtpdec: Don't explicitly include unistd.h any longer

Conflicts:
	configure

Merged-by: Michael Niedermayer <michaelni@gmx.at>