meson: options: Add option to select the Android platform

The Android Camera3 HAL implementation requires platform
specific extensions, such as the selection of the memory backend
to use and additional constraints depending on the target device.

Define a combo option to select which platform to target and
define the currently existing implementation as 'generic'.

Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

meson_options.txt

@@ -5,6 +5,12 @@ option('android',
         value : 'disabled',
         description : 'Compile libcamera with Android Camera3 HAL interface')
 
+option('android_platform',
+        type : 'combo',
+        choices : ['generic'],
+        value : 'generic',
+        description : 'Select the Android platform to compile for')
+
 option('documentation',
         type : 'feature',
         description : 'Generate the project documentation')