build/meson: Add systemd feature option for monado-service

meson.build

@@ -71,6 +71,7 @@ vulkan   = dependency('vulkan', required: true)
 zlib     = dependency('zlib', required: false)
 survive  = dependency('survive', required: false)
 dbus     = dependency('dbus-1', required: get_option('dbus'))
+systemd  = dependency('libsystemd', required: get_option('systemd'))
 gst      = dependency('gstreamer-1.0', required: false)
 gst_app  = dependency('gstreamer-app-1.0', required: false)
 gst_video= dependency('gstreamer-video-1.0', required: false)

meson_options.txt

@@ -77,6 +77,11 @@ option('dbus',
 	value: 'auto',
 	description: 'Enable support for dbus.')
 
+option('systemd',
+	type: 'feature',
+	value: 'auto',
+	description: 'Enable systemd support (for socket activation of service)')
+
 option('service',
 	type: 'boolean',
 	value: true,

src/xrt/include/xrt/meson.build

@@ -76,6 +76,10 @@ if dbus.found() and not get_option('dbus').disabled()
 	have_conf.set('XRT_HAVE_DBUS', true)
 endif
 
+if systemd.found() and not get_option('systemd').disabled()
+	have_conf.set('XRT_HAVE_SYSTEMD', true)
+endif
+
 if get_option('layer_depth')
 	have_conf.set('XRT_FEATURE_OPENXR_LAYER_DEPTH', true)
 endif

src/xrt/targets/service/meson.build

@@ -1,6 +1,11 @@
 # Copyright 2020, Collabora, Ltd.
 # SPDX-License-Identifier: BSL-1.0
 
+service_deps = [pthreads, libjpeg]
+if systemd.found() and not get_option('systemd').disabled()
+	service_deps += systemd
+endif
+
 hack_deps = []
 hack_src = [ '../openxr/oxr_sdl2_hack.c']
 hack_libs = []
@@ -41,6 +46,6 @@ service = executable(
 		common_include,
 		xrt_include,
 	] + hack_incs,
-	dependencies: [pthreads, libjpeg] + hack_deps,
+	dependencies: [pthreads, libjpeg] + hack_deps + service_deps,
 	install: true,
 )