Implement HAL and apply macros across code-base

Implement AVR Platform

Marlin/src/HAL/HAL_spi_pins.h

@@ -0,0 +1,39 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * 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/>.
+ *
+ */
+
+
+#ifndef HAL_SPI_PINS_H_
+#define HAL_SPI_PINS_H_
+
+#include "MarlinConfig.h"
+
+#ifdef ARDUINO_ARCH_SAM
+  #include "HAL_DUE/spi_pins.h"
+
+#elif defined(IS_32BIT_TEENSY)
+  #include "HAL_TEENSY35_36/spi_pins.h"
+
+#elif defined(ARDUINO_ARCH_AVR)
+  #include "HAL_AVR/spi_pins.h"
+
+#else
+  #error "Unsupported Platform!"
+#endif
+
+#endif /* HAL_SPI_PINS_H_ */