Start fleshing out wayland client implementation

This introduces a basic shared framework for making wayland clients
within sway itself.

common/list.c

@@ -0,0 +1,55 @@
+#include "list.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+list_t *create_list(void) {
+	list_t *list = malloc(sizeof(list_t));
+	list->capacity = 10;
+	list->length = 0;
+	list->items = malloc(sizeof(void*) * list->capacity);
+	return list;
+}
+
+static void list_resize(list_t *list) {
+	if (list->length == list->capacity) {
+		list->capacity += 10;
+		list->items = realloc(list->items, sizeof(void*) * list->capacity);
+	}
+}
+
+void list_free(list_t *list) {
+	if (list == NULL) {
+		return;
+	}
+	free(list->items);
+	free(list);
+}
+
+void list_add(list_t *list, void *item) {
+	list_resize(list);
+	list->items[list->length++] = item;
+}
+
+void list_insert(list_t *list, int index, void *item) {
+	list_resize(list);
+	memmove(&list->items[index + 1], &list->items[index], sizeof(void*) * (list->length - index));
+	list->length++;
+	list->items[index] = item;
+}
+
+void list_del(list_t *list, int index) {
+	list->length--;
+	memmove(&list->items[index], &list->items[index + 1], sizeof(void*) * (list->length - index));
+}
+
+void list_cat(list_t *list, list_t *source) {
+	int i;
+	for (i = 0; i < source->length; ++i) {
+		list_add(list, source->items[i]);
+	}
+}
+
+void list_sort(list_t *list, int compare(const void *left, const void *right)) {
+	qsort(list->items, list->length, sizeof(void *), compare);
+}