add docs option to build - allow it to be explicitly on or off

meson.build

@@ -618,9 +618,11 @@ foreach evas_loader_map_inst : evas_loader_map
   meson.add_install_script('meson/evas_loader_conf.sh', evas_loader_original, evas_loader_link_types)
 endforeach
 
-doxygen = find_program('doxygen', required : false)
-
-if doxygen.found()
+doxygen = find_program('doxygen', required : get_option('docs'))
+if get_option('docs')
+  if not doxygen.found()
+    error('Need doxygen for docs')
+  endif
   subdir('doc')
 endif
 

meson_options.txt

@@ -382,3 +382,9 @@ option('max-fd-size',
   value : '8192',
   description : 'This is the maximim set of fds and thus maximum fd value allowed +1 in the ecore main loop handler'
 )
+
+option('docs',
+  type: 'boolean',
+  value: false,
+  description: 'Enable building C of documentation (Requires doxygen)'
+)