The added patch uses mach_absolute_time() to get a nanosecond-resolution monotonic clock on darwin systems (See http://developer.apple.com/library/mac/#qa/qa1398/_index.html for an understanding of the added code). In addition, the patch changes one use of clock_gettime to gettimeofday since only resolution of a second is needed at that point. This code compiles on darwin, but the resulting library is not yet tested.
svn path=/nixpkgs/trunk/; revision=28879
