[opencv4] allow wasm build (#52480)

ports/opencv4/portfile.cmake

@@ -140,6 +140,7 @@ vcpkg_check_features(OUT_FEATURE_OPTIONS FEATURE_OPTIONS
  "text"       BUILD_opencv_text
  "text"       WITH_TESSERACT
  "tiff"       WITH_TIFF
+ "v4l"        WITH_V4L
  "vtk"        WITH_VTK
  "vulkan"     WITH_VULKAN
  "webp"       WITH_WEBP

ports/opencv4/vcpkg.json

@@ -1,7 +1,7 @@
 {
   "name": "opencv4",
   "version": "4.12.0",
-  "port-version": 3,
+  "port-version": 4,
   "description": "Open Source Computer Vision Library",
   "homepage": "https://opencv.org/",
   "documentation": "https://docs.opencv.org/4.12.0/",
@@ -56,6 +56,10 @@
     "quirc",
     "thread",
     "tiff",
+    {
+      "name": "v4l",
+      "platform": "linux"
+    },
     "webp",
     {
       "name": "win32ui",
@@ -488,6 +492,10 @@
         }
       ]
     },
+    "v4l": {
+      "description": "Video4Linux support for opencv",
+      "supports": "linux"
+    },
     "vtk": {
       "description": "vtk support for opencv",
       "dependencies": [

versions/baseline.json

@@ -7402,7 +7402,7 @@
     },
     "opencv4": {
       "baseline": "4.12.0",
-      "port-version": 3
+      "port-version": 4
     },
     "opendnp3": {
       "baseline": "3.1.2",

versions/o-/opencv4.json

@@ -1,5 +1,10 @@
 {
   "versions": [
+    {
+      "git-tree": "7e25a9ac702b9b94264dc469895c06e82b62d283",
+      "version": "4.12.0",
+      "port-version": 4
+    },
     {
       "git-tree": "0022247a58e672802c0a0beed9515b6a5288a244",
       "version": "4.12.0",