ntdll: Added NtGetTickCount implementation.

dlls/ntdll/ntdll.spec

@@ -177,7 +177,7 @@
 @ stdcall NtGetContextThread(long ptr)
 # @ stub NtGetDevicePowerState
 @ stub NtGetPlugPlayEvent
-@ stub NtGetTickCount
+@ stdcall NtGetTickCount()
 # @ stub NtGetWriteWatch
 @ stub NtImpersonateAnonymousToken
 @ stub NtImpersonateClientOfPort
@@ -1019,7 +1019,7 @@
 @ stdcall ZwGetContextThread(long ptr) NtGetContextThread
 # @ stub ZwGetDevicePowerState
 @ stub ZwGetPlugPlayEvent
-@ stub ZwGetTickCount
+@ stdcall ZwGetTickCount() NtGetTickCount
 # @ stub ZwGetWriteWatch
 # @ stub ZwImpersonateAnonymousToken
 @ stub ZwImpersonateClientOfPort

dlls/ntdll/time.c

@@ -877,6 +877,20 @@ NTSTATUS WINAPI NtQueryPerformanceCounter( PLARGE_INTEGER Counter, PLARGE_INTEGE
     return STATUS_SUCCESS;
 }
 
+
+/******************************************************************************
+ * NtGetTickCount   (NTDLL.@)
+ * ZwGetTickCount   (NTDLL.@)
+ */
+ULONG WINAPI NtGetTickCount(void)
+{
+    struct timeval current_time;
+
+    gettimeofday(&current_time, NULL);
+    return (current_time.tv_sec - server_start_time)*1000 + current_time.tv_usec/1000;
+}
+
+
 /***********************************************************************
  *        TIME_GetTZAsStr [internal]
  *