Shorter paths to HAL, ExtUI (#17156)

Marlin/src/HAL/LINUX/hardware/Clock.cpp

@@ -0,0 +1,32 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifdef __PLAT_LINUX__
+
+#include "../../../inc/MarlinConfig.h"
+#include "Clock.h"
+
+std::chrono::nanoseconds Clock::startup = std::chrono::high_resolution_clock::now().time_since_epoch();
+uint32_t Clock::frequency = F_CPU;
+double Clock::time_multiplier = 1.0;
+
+#endif // __PLAT_LINUX__