[ST-devel] st-1.5.0 patch

[<ge...@co...>]

A small patch to add a new function allowing to replace the default
implementation of st_utime() with the user-provided one.
On Linux/FreeBSD/etc. st_utime() is implemented via gettimeofday()
(a syscall). Sometimes it's desirable to use hi-res time function
implemented more efficiently, e.g. by reading CPU cycle counter.
This patch adds ability to plug in user's implementation of st_utime().