asahi: build asahi_clc for -Dtools=asahi

This allows building tools for cross-compiling without building gallium
or vulkan drivers unnecessarily.

Backport-to: 25.1
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Janne Grunau <j@jannau.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34693>
(cherry picked from commit 007d7418f8fb41c1ea789f5049be023312802048)

.pick_status.json

@@ -254,7 +254,7 @@
         "description": "asahi: build asahi_clc for -Dtools=asahi",
         "nominated": true,
         "nomination_type": 4,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null,
         "notes": null

src/asahi/meson.build

@@ -9,12 +9,15 @@ inc_asahi = include_directories([
    '.', 'layout', 'lib', 'genxml', 'compiler'
 ])
 
-if with_gallium_asahi or with_asahi_vk
+if with_gallium_asahi or with_asahi_vk or with_tools.contains('asahi')
    subdir('genxml')
    subdir('libagx')
-   subdir('layout')
    subdir('compiler')
    subdir('clc')
+endif
+
+if with_gallium_asahi or with_asahi_vk
+   subdir('layout')
    subdir('lib')
 elif dep_iokit.found()
    # Just build enough for libwrap.dylib