libcamera: Add option to configure udev support

libcamera uses udev to support hotplug (and unplug) detection. This is
an optional feature, which gets selected automatically if udev is
available. Users may however want to build libcamera without hotplug
detection, even if udev is available on the system. Add a new feature
option to control udev support. The default value is auto, which retains
the existing behaviour.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/meson.build

@@ -76,7 +76,7 @@ libdl = null_dep
 if not cc.has_function('dlopen')
     libdl = cc.find_library('dl')
 endif
-libudev = dependency('libudev', required : false)
+libudev = dependency('libudev', required : get_option('udev'))
 libyaml = dependency('yaml-0.1', required : false)
 
 # Use one of gnutls or libcrypto (provided by OpenSSL), trying gnutls first.