meson: Add apps-output-dng option to control libtiff dependency

Previously it was not possible to disable the use of libtiff in the cam
and qcam applications if it was detected. Fix that by adding a meson
feature option.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

meson_options.txt

@@ -62,6 +62,11 @@ option('libdw',
         value : 'auto',
         description : 'Enable libdw integration for backtrace symbolization')
 
+option('apps-output-dng',
+        type : 'feature',
+        value : 'auto',
+        description : 'Enable DNG file creation support in the cam and qcam applications')
+
 option('libunwind',
         type : 'feature',
         value : 'auto',

src/apps/meson.build

@@ -10,7 +10,7 @@ if not libevent.found()
     libevent = dependency('libevent_pthreads', required : opt_lc_compliance)
 endif
 
-libtiff = dependency('libtiff-4', required : false)
+libtiff = dependency('libtiff-4', required : get_option('apps-output-dng'))
 
 subdir('common')