meson: fix build with missing libudev-devel

(cherry picked from commit b4c7973d49)

spa/meson.build

@@ -104,7 +104,8 @@ if get_option('spa-plugins').allowed()
   cdata.set('HAVE_ALSA_COMPRESS_OFFLOAD', compress_offload_option.allowed())
 
   # common dependencies
-  libudev_dep = dependency('libudev', required: alsa_dep.found() or get_option('udev').enabled() or get_option('v4l2').enabled())
+  libudev_dep = dependency('libudev', required: get_option('udev').enabled())
+  cdata.set('HAVE_LIBUDEV', libudev_dep.found())
   summary({'Udev': libudev_dep.found()}, bool_yn: true, section: 'Backend')
 
   subdir('plugins')

spa/plugins/alsa/alsa.c

@@ -38,8 +38,13 @@ int spa_handle_factory_enum(const struct spa_handle_factory **factory, uint32_t
 		*factory = &spa_alsa_sink_factory;
 		break;
 	case 2:
+#ifdef HAVE_LIBUDEV
 		*factory = &spa_alsa_udev_factory;
 		break;
+#else
+		(*index)++;
+		SPA_FALLTHROUGH;
+#endif
 	case 3:
 		*factory = &spa_alsa_pcm_device_factory;
 		break;

spa/plugins/alsa/meson.build

@@ -1,11 +1,10 @@
 subdir('acp')
 subdir('mixer')
 
-spa_alsa_dependencies = [ spa_dep, alsa_dep, libudev_dep, mathlib, epoll_shim_dep, libinotify_dep ]
+spa_alsa_dependencies = [ spa_dep, alsa_dep, mathlib, epoll_shim_dep, libinotify_dep ]
 
 spa_alsa_sources = ['alsa.c',
                 'alsa.h',
-                'alsa-udev.c',
                 'alsa-acp-device.c',
                 'alsa-pcm-device.c',
                 'alsa-pcm-sink.c',
@@ -14,6 +13,11 @@ spa_alsa_sources = ['alsa.c',
                 'alsa-seq-bridge.c',
                 'alsa-seq.c']
 
+if libudev_dep.found()
+spa_alsa_sources += [ 'alsa-udev.c' ]
+spa_alsa_dependencies += [ libudev_dep ]
+endif
+
 if compress_offload_option.allowed()
   spa_alsa_sources += ['alsa-compress-offload-sink.c',
                        'alsa-compress-offload-device.c',

spa/plugins/libcamera/meson.build

@@ -8,6 +8,6 @@ libcamera_sources = [
 libcameralib = shared_library('spa-libcamera',
   libcamera_sources,
   include_directories : [ configinc ],
-  dependencies : [ spa_dep, libudev_dep, libcamera_dep, pthread_lib  ],
+  dependencies : [ spa_dep, libcamera_dep, pthread_lib  ],
   install : true,
   install_dir : spa_plugindir / 'libcamera')

spa/plugins/meson.build

@@ -45,10 +45,9 @@ if have_vulkan
 endif
 
 v4l2_header_found = cc.has_header('linux/videodev2.h', required: get_option('v4l2'))
-v4l2_supported = libudev_dep.found() and v4l2_header_found
 summary({'V4L2 kernel header': v4l2_header_found}, bool_yn: true, section: 'Backend')
-summary({'V4L2 enabled': v4l2_supported}, bool_yn: true, section: 'Backend')
+summary({'V4L2 enabled': v4l2_header_found}, bool_yn: true, section: 'Backend')
-if v4l2_supported
+if v4l2_header_found
   subdir('v4l2')
 endif
 if libcamera_dep.found()

spa/plugins/v4l2/meson.build

@@ -1,10 +1,15 @@
 v4l2_sources = ['v4l2.c',
                 'v4l2-device.c',
-                'v4l2-udev.c',
                 'v4l2-source.c']
+v4l2_dependencies = [ spa_dep, libinotify_dep ]
+
+if libudev_dep.found()
+v4l2_sources += [ 'v4l2-udev.c' ]
+v4l2_dependencies += [ libudev_dep ]
+endif
 
 v4l2lib = shared_library('spa-v4l2',
                           v4l2_sources,
-                          dependencies : [ spa_dep, libudev_dep, libinotify_dep ],
+                          dependencies : v4l2_dependencies,
                           install : true,
                           install_dir : spa_plugindir / 'v4l2')

spa/plugins/v4l2/v4l2.c

@@ -27,8 +27,13 @@ int spa_handle_factory_enum(const struct spa_handle_factory **factory,
 		*factory = &spa_v4l2_source_factory;
 		break;
 	case 1:
+#ifdef HAVE_LIBUDEV
 		*factory = &spa_v4l2_udev_factory;
 		break;
+#else
+		(*index)++;
+		SPA_FALLTHROUGH;
+#endif
 	case 2:
 		*factory = &spa_v4l2_device_factory;
 		break;