soup: Re-add soup-lookup-dep option

It's still useful on Linux since it ensures that the tests are going
to be built, since they use the same dep lookup as the plugin now.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6198>

.gitlab-ci.yml

@@ -40,6 +40,7 @@ variables:
     -Dlibnice:tests=disabled
     -Dlibnice:examples=disabled
     -Dopenh264:tests=disabled
+    -Dgst-plugins-good:soup-lookup-dep=true
     -Dpygobject:tests=false
     -Dpython=enabled
     -Dlibav=enabled
@@ -414,6 +415,7 @@ build vs2019 arm64 uwp:
     MESON_CROSS_ARGS: >
       -Dgst-plugins-base:pango=disabled
       -Dgst-plugins-good:cairo=disabled
+      -Dgst-plugins-good:soup=disabled
       -Dgst-devtools:cairo=disabled
       --cross-file ci/meson/vs2019-arm64-cross-file.txt
       --native-file ci/meson/vs2019-x64-native-file.txt

subprojects/gst-plugins-good/ext/soup/meson.build

@@ -20,7 +20,8 @@ soup_link_deps = []
 libsoup2_dep = disabler()
 libsoup3_dep = disabler()
 default_library = get_option('default_library')
-if host_system != 'linux' or default_library in ['static', 'both']
+soup_lookup_dep = get_option('soup-lookup-dep') and host_system == 'linux'
+if host_system != 'linux' or default_library in ['static', 'both'] or soup_lookup_dep
   if soup_ver_opt in ['auto', '3']
     libsoup3_dep = dependency('libsoup-3.0', allow_fallback: true,
                               required: soup_ver_opt == '3' and soup_opt.enabled())

subprojects/gst-plugins-good/meson_options.txt

@@ -85,6 +85,8 @@ option('rpi-lib-dir', type : 'string', value : '/opt/vc/lib', description : 'Dir
 
 # soup plugin options
 option('soup', type : 'feature', value : 'auto', description : 'libsoup HTTP client source/sink plugin')
+option('soup-lookup-dep', type : 'boolean', value : false,
+       description : 'Lookup libsoup dep at build time even when building a shared plugin')
 option('soup-version', type : 'combo', value : 'auto', choices : ['auto', '2', '3'],
        description: 'Force a specific libsoup version if linking to it (N/A for shared builds on Linux)')