ci: build docs using meson

To avoid having to inflate the image here even further, let's just add
what we need to the the normal x86 Alpine build image, and use that.

Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Eric Engestrom <eric@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11494>

docs/gitlab-ci.yml

@@ -1,21 +1,21 @@
 .docs-base:
-  variables:
-    BUILDER: html
   extends:
-    - .fdo.ci-fairy
+    - .build-linux
+    - .use-alpine/x86_64_build
   artifacts:
     expose_as: 'Documentation preview'
     paths:
     - public/
   script:
-  - apk --no-cache add coreutils graphviz py3-clang clang-dev musl-dev linux-headers
-  - pip3 install sphinx===5.1.1 mako===1.2.3 hawkmoth===0.16.0
-  - sphinx-build -W -b $BUILDER docs public
+    - meson setup _build -D prefix=$(pwd) --auto-features=disabled
+      -D vulkan-drivers="" -D gallium-drivers="" -D glx=disabled
+      -D video-codecs="" -D html-docs=enabled -D html-docs-path=public
+    - meson compile -C _build
+    - meson install -C _build
 
 pages:
   extends: .docs-base
   stage: deploy
-  needs: []
   rules:
     - !reference [.no_scheduled_pipelines-rules, rules]
     - if: '$CI_PROJECT_NAMESPACE == "mesa" && $CI_COMMIT_REF_NAME == $CI_DEFAULT_BRANCH && $CI_COMMIT_BRANCH'
@@ -35,7 +35,6 @@ test-docs:
   # Cancel job if a newer commit is pushed to the same branch
   interruptible: true
   stage: deploy
-  needs: []
   rules:
     - !reference [.no_scheduled_pipelines-rules, rules]
     - if: '$CI_COMMIT_BRANCH && $CI_PROJECT_NAMESPACE != "mesa"'
@@ -46,9 +45,6 @@ test-docs:
 test-docs-mr:
   extends:
     - test-docs
-  needs:
-    - job: sanity
-      optional: true
   rules:
     - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
       changes: *docs-or-ci
@@ -60,10 +56,8 @@ linkcheck-docs:
   # Cancel job if a newer commit is pushed to the same branch
   interruptible: true
   stage: deploy
-  needs: []
   rules:
     - !reference [.scheduled_pipeline-rules, rules]
   allow_failure: true
-  variables:
-    BUILDER: linkcheck
-
+  script:
+    - sphinx-build -W -b linkcheck docs public