build/gi: Set header & pkgconfig names

So that the docs generated by gi-docgen contains them

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3087>

clutter/clutter/meson.build

@@ -376,6 +376,7 @@ if have_introspection
       cally_headers,
     ],
     nsversion: libmutter_api_version,
+    header: 'cally/cally.h',
     namespace: 'Cally',
     includes: [
       libmutter_cogl_gir[0],

cogl/cogl-pango/meson.build

@@ -54,6 +54,7 @@ if have_introspection
       pango_dep,
       libmutter_cogl_pango_dep,
     ],
+    export_packages: 'mutter-cogl-pango-@0@'.format(libmutter_api_version),
     extra_args: introspection_args + [
       '-UCOGL_COMPILATION',
       '-DG_LOG_DOMAIN="CoglPango"',

cogl/cogl/meson.build

@@ -447,6 +447,7 @@ if have_introspection
     namespace: 'Cogl',
     includes: ['cairo-1.0', 'GL-1.0', 'GObject-2.0', 'Graphene-1.0'],
     dependencies: [cogl_deps],
+    export_packages: 'mutter-cogl-@0@'.format(libmutter_api_version),
     extra_args: introspection_args + [
       '-UCOGL_COMPILATION',
       '-D__COGL_H_INSIDE__',

src/meson.build

@@ -1268,6 +1268,7 @@ if have_introspection
       libmutter_dep,
       mutter_deps,
     ],
+    export_packages: 'libmutter-@0@'.format(libmutter_api_version),
     extra_args: mutter_c_args + introspection_args,
     install_dir_gir: pkglibdir,
     install_dir_typelib: pkglibdir,