Revert "Revert "Merge pull request #1194 from ascent12/meson_feature""

This reverts commit 9c886f20b9.

backend/x11/meson.build

@@ -0,0 +1,44 @@
+x11_libs = []
+x11_required = [
+	'xcb',
+	'x11-xcb',
+]
+x11_optional = [
+	'xcb-xkb',
+]
+
+foreach lib : x11_required
+	dep = dependency(lib, required: get_option('x11-backend'))
+	if not dep.found()
+		subdir_done()
+	endif
+
+	x11_libs += dep
+endforeach
+
+foreach lib : x11_optional
+	dep = dependency(lib, required: get_option(lib))
+	if dep.found()
+		x11_libs += dep
+		conf_data.set('WLR_HAS_' + lib.underscorify().to_upper(), true)
+	endif
+endforeach
+
+lib_wlr_backend_x11 = static_library(
+	'wlr_backend_x11',
+	files(
+		'backend.c',
+		'input_device.c',
+		'output.c',
+	),
+	include_directories: wlr_inc,
+	dependencies: [
+		wayland_server,
+		pixman,
+		xkbcommon,
+		x11_libs,
+	],
+)
+
+backend_parts += lib_wlr_backend_x11
+conf_data.set('WLR_HAS_X11_BACKEND', true)