convert to platformio and clean up

src/core.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <Arduino.h>
+
+#define GBCOLOR_HEADER_ONLY
+#include "gbcolors.h"
+
+/* Multicore command structure. */
+union core_cmd
+{
+    struct
+    {
+        /* Does nothing. */
+#define CORE_CMD_NOP 0
+        /* Set line "data" on the LCD. Pixel data is in pixels_buffer. */
+#define CORE_CMD_LCD_LINE 1
+        /* Control idle mode on the LCD. Limits colours to 2 bits. */
+#define CORE_CMD_IDLE_SET 2
+        /* Set a specific pixel. For debugging. */
+#define CORE_CMD_SET_PIXEL 3
+        uint8_t cmd;
+        uint8_t unused1;
+        uint8_t unused2;
+        uint8_t data;
+    };
+    uint32_t full;
+};
+
+
+extern palette_t palette; // Colour palette
+
+void lcd_draw_line(struct gb_s *gb, const uint8_t *pixels, const uint_fast8_t line);
+
+void core1_init();