Convert from Xlib xcb

This will make it easier to convert this project to Go/xgb later,
even though the SYNC extension isn't currently supported there.

So far unresolved: error handling.

meson.build

@@ -19,14 +19,13 @@ dependencies = [
 	dependency('gio-unix-2.0'),
 	dependency('gee-0.8'),
 	dependency('sqlite3'),
-	dependency('x11'),
-	dependency('xext'),
-	dependency('xextproto'),
+	dependency('xcb'),
+	dependency('xcb-sync'),
 ]
 gui = static_library('gui', 'gui.vala', 'config.vapi',
 	install : false,
 	dependencies : dependencies)
-executable('wdmtg', 'wdmtg.c',
+executable('wdmtg', 'wdmtg.c', 'compound-text.c',
 	install : true,
 	link_with : [gui],
 	dependencies : [dependencies])