meson: use a feature option for shared-glapi

Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20409>

meson.build

@@ -134,19 +134,9 @@ endif
 with_opengl = get_option('opengl')
 
 # Default shared glapi off for windows, on elsewhere.
-_sg = get_option('shared-glapi')
-if _sg == 'true'
-  _sg = 'enabled'
-  warning('shared-glapi option "true" deprecated, please use "enabled" instead.')
-elif _sg == 'false'
-  _sg = 'disabled'
-  warning('shared-glapi option "false" deprecated, please use "disabled" instead.')
-endif
-if _sg == 'auto'
-  with_shared_glapi = host_machine.system() != 'windows'
-else
-  with_shared_glapi = _sg == 'enabled'
-endif
+with_shared_glapi = get_option('shared-glapi') \
+  .disable_auto_if(host_machine.system() == 'windows') \
+  .allowed()
 
 # shared-glapi is required if at least two OpenGL APIs are being built
 if not with_shared_glapi

meson_options.txt

@@ -241,9 +241,7 @@ option(
 )
 option(
   'shared-glapi',
-  type : 'combo',
-  value : 'auto',
-  choices : ['auto', 'true', 'false', 'enabled', 'disabled'],
+  type : 'feature',
   description : 'Whether to build a shared or static glapi. Defaults to false on Windows, true elsewhere'
 )
 option(