Fix sign error in SYSTEM_CLOCK kind=4 Windows version.

2013-04-28  Janne Blomqvist  <jb@gcc.gnu.org>

	* intrinsics/system_clock.c (system_clock_4): Fix sign error in
	Windows version.

From-SVN: r198378

libgfortran/ChangeLog

+2013-04-28  Janne Blomqvist  <jb@gcc.gnu.org>
+
+	* intrinsics/system_clock.c (system_clock_4): Fix sign error in
+	Windows version.
+
 2013-04-15  Tobias Burnus  <burnus@net-b.de>
 
 	* list_read.c (finish_separator): Initialize variable.
@@ -37,7 +42,7 @@
 	(nml_get_obj_data): Likewise use the correct error mechanism.
 	* io/transfer.c (hit_eof): Do not set AFTER_ENDFILE if in namelist
 	mode.
-	
+
 2013-03-29  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/56737

libgfortran/intrinsics/system_clock.c

@@ -134,7 +134,7 @@ system_clock_4(GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
 	 QueryPerformanceCounter has potential issues.  */
       uint32_t cnt = GetTickCount ();
       if (cnt > GFC_INTEGER_4_HUGE)
-	cnt -= GFC_INTEGER_4_HUGE - 1;
+	cnt = cnt - GFC_INTEGER_4_HUGE - 1;
       *count = cnt;
     }
   if (count_rate)