meson: Fixed remaining issues from the port to `feature` options

meson_options.txt

@@ -38,7 +38,7 @@ option('systemd',
 option('systemd-system-service',
        description: 'Install systemd system service file',
        type: 'feature',
-       value: 'auto')
+       value: 'disabled')
 option('systemd-user-service',
        description: 'Install systemd user service file',
        type: 'feature',
@@ -124,8 +124,8 @@ option('v4l2',
        value: 'auto')
 option('libcamera',
        description: 'Enable libcamera spa plugin integration',
-       type: 'boolean',
-       value: false)
+       type: 'feature',
+       value: 'auto')
 option('videoconvert',
        description: 'Enable videoconvert spa plugin integration',
        type: 'feature',

src/examples/meson.build

@@ -65,7 +65,7 @@ executable('export-spa-device',
   dependencies : [pipewire_dep, mathlib],
 )
 
-if alsa_dep.found()
+if not get_option('media-session').disabled() and alsa_dep.found()
   executable('pipewire-media-session',
     'media-session/access-flatpak.c',
     'media-session/access-portal.c',
@@ -94,8 +94,6 @@ if alsa_dep.found()
     install: true,
     dependencies : [dbus_dep, pipewire_dep, alsa_dep, mathlib],
 )
-elif get_option('media-session').enabled() and not alsa_dep.found()
-  error('`media-session` is enabled but required dependency `alsa` not found.')
 endif
 
 executable('pw-reserve',

src/meson.build

@@ -11,4 +11,6 @@ if not get_option('tests').disabled()
   subdir('tests')
 endif
 
-subdir('gst')
+if gst_dep.length() != 0
+  subdir('gst')
+endif