Move whole tile-producing function onto the C++ side

tile.h

@@ -0,0 +1,45 @@
+#define VT_END 0
+#define VT_POINT 1
+#define VT_LINE 2
+#define VT_POLYGON 3
+
+#define VT_MOVETO 1
+#define VT_LINETO 2
+#define VT_CLOSEPATH 7
+
+#define VT_STRING 1
+#define VT_NUMBER 2
+#define VT_BOOLEAN 7
+
+
+
+
+struct pool_val {
+	char *s;
+	int type;
+	int n;
+
+	struct pool_val *next;
+};
+
+struct pool {
+	struct pool_val *vals;
+	int n;
+};
+
+
+void deserialize_int(char **f, int *n);
+struct pool_val *deserialize_string(char **f, struct pool *p, int type);
+void pool_free(struct pool *p);
+
+
+struct index {
+        unsigned long long index;
+        long long fpos;
+
+        struct index *next;
+};
+
+
+void write_tile(char *name, struct pool *keys);
+void check_range(struct index *start, struct index *end, char *metabase, unsigned *file_bbox);