[gtk: 1/2] meson: Change introspection option to yielding feature

[Matthias Clasen <matthiasc src gnome org>]

commit 0e5dac8c25d11e3ce921c584c05064a93507393d
Author: Xavier Claessens <xavier claessens collabora com>
Date:   Wed Sep 30 09:41:28 2020 -0400

    meson: Change introspection option to yielding feature
    
    Yielding option means that if pango is built as a subproject, it will
    take the value of that option from the parent project (e.g. gst-build).
    For that to work it must be of the same type, which is "feature" instead
    of "boolean" in all GStreamer modules.

 .gitlab-ci.yml              | 2 +-
 .gitlab-ci/flatpak-build.sh | 2 +-
 .gitlab-ci/test-msys2.sh    | 2 +-
 gtk/meson.build             | 5 ++++-
 meson.build                 | 2 +-
 meson_options.txt           | 5 +++--
 6 files changed, 11 insertions(+), 7 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 832880d617..2f425ca327 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -223,7 +223,7 @@ asan-build:
   needs: []
   variables:
   script:
-    - CC=clang meson --buildtype=debugoptimized -Db_sanitize=address -Db_lundef=false -Dintrospection=false 
_build
+    - CC=clang meson --buildtype=debugoptimized -Db_sanitize=address -Db_lundef=false 
-Dintrospection=disabled _build
     - ninja -C _build
     - .gitlab-ci/run-tests.sh _build wayland
   artifacts:
diff --git a/.gitlab-ci/flatpak-build.sh b/.gitlab-ci/flatpak-build.sh
index cbb6c097d1..531741db1d 100644
--- a/.gitlab-ci/flatpak-build.sh
+++ b/.gitlab-ci/flatpak-build.sh
@@ -22,7 +22,7 @@ flatpak build ${builddir} meson \
                 -Dprint-backends=file \
                 -Dbuild-tests=false \
                 -Dbuild-examples=false \
-                -Dintrospection=false \
+                -Dintrospection=disabled \
                 -Ddemos=true \
                 _flatpak_build
 
diff --git a/.gitlab-ci/test-msys2.sh b/.gitlab-ci/test-msys2.sh
index d311f4bbe7..dfa8813240 100644
--- a/.gitlab-ci/test-msys2.sh
+++ b/.gitlab-ci/test-msys2.sh
@@ -67,7 +67,7 @@ meson \
     -Dwayland-backend=false \
     -Dwin32-backend=true \
     -Dvulkan=disabled \
-    -Dintrospection=false \
+    -Dintrospection=disabled \
     -Dgtk:werror=true \
     _build
 unset CCACHE_DISABLE
diff --git a/gtk/meson.build b/gtk/meson.build
index 3554c1b2f1..3e18f05cb6 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -1075,8 +1075,11 @@ libgtk = library('gtk-4',
                  install: true)
 
 gtk_dep_sources = [gtkversion, gtktypebuiltins_h]
+
 # Introspection
-build_gir = get_option('introspection')
+gir = find_program('g-ir-scanner', required : get_option('introspection'))
+build_gir = gir.found() and (not meson.is_cross_build() or get_option('introspection').enabled())
+
 if build_gir
   gir_args = [
     '-DGTK_COMPILATION',
diff --git a/meson.build b/meson.build
index 127671a349..6ad27d2158 100644
--- a/meson.build
+++ b/meson.build
@@ -876,7 +876,7 @@ summary('Tracker support', tracker3_dep.found(), section: 'Features')
 # Build
 summary('Debugging', get_option('debug'), section: 'Build')
 summary('Optimization', get_option('optimization'), section: 'Build')
-summary('Introspection', get_option('introspection'), section: 'Build')
+summary('Introspection', build_gir, section: 'Build')
 summary('Documentation', get_option('gtk_doc'), section: 'Build')
 summary('Man pages', get_option('man-pages'), section: 'Build')
 summary('Tests', get_option('build-tests'), section: 'Build')
diff --git a/meson_options.txt b/meson_options.txt
index f4dc3b43d7..b58c8a9fa0 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -84,8 +84,9 @@ option('man-pages',
        description : 'Build man pages for installed tools')
 
 option('introspection',
-       type: 'boolean',
-       value: 'true',
+       type: 'feature',
+       value: 'auto',
+       yield: true,
        description : 'Build introspection data (requires gobject-introspection)')
 
 # Demos, examples and tests