[qtbase] Add feature for gtk3 platform theme (#35657)

ports/qtbase/portfile.cmake

@@ -258,12 +258,12 @@ endforeach()
     # )
 list(APPEND FEATURE_PRINTSUPPORT_OPTIONS -DCMAKE_DISABLE_FIND_PACKAGE_CUPS:BOOL=ON)
 
-# widgets features:
-# vcpkg_check_features(OUT_FEATURE_OPTIONS FEATURE_WIDGETS_OPTIONS
-    # "gtk3"             FEATURE_gtk3
-    # There are a lot of additional features here to deactivate parts of widgets.
-    # )
-list(APPEND FEATURE_WIDGETS_OPTIONS -DCMAKE_DISABLE_FIND_PACKAGE_GTK3:BOOL=ON)
+vcpkg_check_features(OUT_FEATURE_OPTIONS FEATURE_WIDGETS_OPTIONS
+    FEATURES
+    "gtk3"              FEATURE_gtk3
+    INVERTED_FEATURES
+    "gtk3"              CMAKE_DISABLE_FIND_PACKAGE_GTK3
+)
 
 set(TOOL_NAMES
         androiddeployqt

ports/qtbase/vcpkg.json

@@ -1,7 +1,7 @@
 {
   "name": "qtbase",
   "version": "6.6.1",
-  "port-version": 2,
+  "port-version": 3,
   "description": "Qt Application Framework Base Module. Includes Core, GUI, Widgets, Networking, SQL, Concurrent and other essential qt components.",
   "homepage": "https://www.qt.io/",
   "license": null,
@@ -207,6 +207,20 @@
         "glib"
       ]
     },
+    "gtk3": {
+      "description": "GTK3 platform theme plugin",
+      "supports": "linux",
+      "dependencies": [
+        "gtk3",
+        {
+          "name": "qtbase",
+          "default-features": false,
+          "features": [
+            "glib"
+          ]
+        }
+      ]
+    },
     "gui": {
       "description": "Qt Gui",
       "dependencies": [

versions/baseline.json

@@ -7110,7 +7110,7 @@
     },
     "qtbase": {
       "baseline": "6.6.1",
-      "port-version": 2
+      "port-version": 3
     },
     "qtcharts": {
       "baseline": "6.6.1",

versions/q-/qtbase.json

@@ -1,5 +1,10 @@
 {
   "versions": [
+    {
+      "git-tree": "b85d2c16c027edb173f51037d9c5a3e05746efa0",
+      "version": "6.6.1",
+      "port-version": 3
+    },
     {
       "git-tree": "43986c6051eb870340850c13b94ea6cb9a28925c",
       "version": "6.6.1",