PR 56919 Improve SYSTEM_CLOCK intrinsic on Windows.

PR 56919 Improve SYSTEM_CLOCK intrinsic on Windows.

frontend ChangeLog:

2013-04-15  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/56919
	* intrinsics.texi (SYSTEM_CLOCK): Update documentation.

libgfortran ChangeLog:

2013-04-15  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/56919
	* intrinsics/time_1.h: Check __CYGWIN__ in addition to
	__MINGW32__.
	* intrinsics/system_clock.c (GF_CLOCK_MONOTONIC): Check
	_POSIX_MONOTONIC_CLOCK as well.
	(system_clock_4): Use GetTickCount on Windows.
	(system_clock_8): Use QueryPerformanceCounter and
	QueryPerformanceCounterFrequency on Windows.

From-SVN: r197968