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

This breaks wlroots when used as a meson subproject.

This reverts commit dea311992e, reversing
changes made to 6db9c4b746.

backend/meson.build

@@ -1,4 +1,3 @@
-backend_parts = []
 backend_files = files(
 	'backend.c',
 	'drm/atomic.c',
@@ -45,17 +44,28 @@ else
 	backend_files += files('session/direct.c')
 endif
 
-if logind.found()
+if conf_data.get('WLR_HAS_SYSTEMD', false)
 	backend_files += files('session/logind.c')
-	backend_deps += logind
+	backend_deps += systemd
 endif
 
-subdir('x11')
+if conf_data.get('WLR_HAS_X11_BACKEND', false)
+	backend_files += files(
+		'x11/backend.c',
+		'x11/input_device.c',
+		'x11/output.c',
+	)
+	backend_deps += xcb_xkb
+endif
+
+if conf_data.get('WLR_HAS_ELOGIND', false)
+	backend_files += files('session/logind.c')
+	backend_deps += elogind
+endif
 
 lib_wlr_backend = static_library(
 	'wlr_backend',
 	backend_files,
 	include_directories: wlr_inc,
-	link_whole: backend_parts,
 	dependencies: backend_deps,
 )

backend/x11/meson.build

@@ -1,44 +0,0 @@
-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)