build: Use the new array type

meson 0.44 features a new option type called `array` that allows
more than one string to be passed.

This feature fits perfectly the `enable_extensions` option needs,
so it has been changed to be an `array` type. the option has not
been limited to a set of choices to avoid duplication.

meson.build

@@ -1,6 +1,6 @@
 project('gnome-shell-extensions',
   version: '3.27.1',
-  meson_version: '>= 0.37.0',
+  meson_version: '>= 0.44.0',
   license: 'GPL2+'
 )
 
@@ -56,7 +56,7 @@ all_extensions += [
   'user-theme'
 ]
 
-enabled_extensions = get_option('enable_extensions').split()
+enabled_extensions = get_option('enable_extensions')
 
 if enabled_extensions.length() == 0
   set = get_option('extension_set')

meson_options.txt

@@ -6,8 +6,8 @@ option('extension_set',
 )
 
 option('enable_extensions',
-  type: 'string',
-  value: '',
+  type: 'array',
+  value: [],
   description: 'Space separated list of extensions to enable instead of a predefined set.'
 )