[phobos] std.datetime unittests fail on linux

[SHOO]

When clock_gettime is defined in the inside of druntime, it uses 
clock_gettime and clock_getres.
I thought that choosing a function to get time by templates to avoid the 
link error, but it is pending.

A solution is just what Brad says.

--
SHOO

(2010/12/15 17:03), Walter Bright wrote:
> generated/linux/debug/unittest/std/datetime.o: In function
> `_D3std8datetime5Tick
> s12_staticCtor1OFNeZv':
> /home/walter/cbx/mars/phobos/std/datetime.d:80: undefined reference to
> `clock_ge
> tres'
> generated/linux/debug/unittest/std/datetime.o: In function
> `_D3std8datetime7syst
> imeFNeZS3std8datetime5Ticks':
> /home/--- errorlevel 1
> make[1]: Leaving directory `/home/walter/cbx/mars/phobos'
> walter/cbx/mars/phobos/std/datetime.d:666: undefined reference to
> `clock_gettime
> '
> collect2: ld returned 1 exit status
> make[2]: *** [generated/linux/debug/unittest/std/datetime] Error 1
> make[1]: *** [unittest] Error 2
> make: *** [unittest] Error 2