Rewrite the entire code-base

The following changes are focused upon:
- Modularity
- Doing away with globals
- No heap allocations
- Better command line interface
- Switch from Xlib to XCB
- More verbose type definitions
- Implement a single-file config by utilising X-macros

include/watcher.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <stdbool.h>
+#include <sys/poll.h>
+
+#include "main.h"
+#include "util.h"
+
+typedef enum {
+    SIGNAL_FD = LEN(blocks),
+    WATCHER_FD_COUNT,
+} watcher_fd_index;
+
+typedef struct pollfd watcher_fd;
+
+typedef struct {
+    watcher_fd fds[WATCHER_FD_COUNT];
+} watcher;
+
+int watcher_init(watcher *const watcher, const int signal_fd);
+int watcher_poll(watcher *const watcher, const int timeout_ms);
+bool watcher_fd_is_readable(const watcher_fd *const watcher_fd);