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

src/x11.c

@@ -1,25 +1,44 @@
 #include "x11.h"
 
-#include <X11/Xlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <xcb/xcb.h>
+#include <xcb/xproto.h>
 
-static Display *display;
-static Window rootWindow;
+x11_connection *x11_connection_open(void) {
+    xcb_connection_t *const connection = xcb_connect(NULL, NULL);
+    if (xcb_connection_has_error(connection)) {
+        (void)fprintf(stderr, "error: could not connect to the X server\n");
+        return NULL;
+    }
 
-int setupX() {
-    display = XOpenDisplay(NULL);
-    if (!display) {
+    return connection;
+}
+
+void x11_connection_close(xcb_connection_t *const connection) {
+    xcb_disconnect(connection);
+}
+
+int x11_set_root_name(x11_connection *const connection, const char *name) {
+    xcb_screen_t *const screen =
+        xcb_setup_roots_iterator(xcb_get_setup(connection)).data;
+    const xcb_window_t root_window = screen->root;
+
+    const unsigned short name_format = 8;
+    const xcb_void_cookie_t cookie = xcb_change_property(
+        connection, XCB_PROP_MODE_REPLACE, root_window, XCB_ATOM_WM_NAME,
+        XCB_ATOM_STRING, name_format, strlen(name), name);
+
+    xcb_generic_error_t *error = xcb_request_check(connection, cookie);
+    if (error != NULL) {
+        (void)fprintf(stderr, "error: could not set X root name\n");
+        return 1;
+    }
+
+    if (xcb_flush(connection) <= 0) {
+        (void)fprintf(stderr, "error: could not flush X output buffer\n");
         return 1;
     }
 
-    rootWindow = DefaultRootWindow(display);
     return 0;
 }
-
-int closeX() {
-    return XCloseDisplay(display);
-}
-
-void setXRootName(char *str) {
-    XStoreName(display, rootWindow, str);
-    XFlush(display);
-}