tried to fix build failure for web_js but am out of ideas.

-> removed feature.

ports/libwebp/0001-build.patch

@@ -35,3 +35,12 @@ index 9503daacb..2fb9ef137 100644
                               PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
 +                                     ${CMAKE_CURRENT_SOURCE_DIR}/src
                                       ${CMAKE_CURRENT_BINARY_DIR})
+@@ -573,7 +573,7 @@ if(WEBP_BUILD_WEBP_JS)
+                "-s EXPORTED_FUNCTIONS='[\"_WebpToSDL\"]' -s INVOKE_RUN=0 \
+        -s EXTRA_EXPORTED_RUNTIME_METHODS='[\"cwrap\"]'")
+   set_target_properties(webp_js PROPERTIES OUTPUT_NAME webp)
+-  target_compile_definitions(webp_js PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
++  target_compile_definitions(webp_js PUBLIC EMSCRIPTEN WEBP_HAVE_SDL WEBP_HAVE_JUST_SDL_H)
+ 
+   # WASM version
+   add_executable(webp_wasm ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)

ports/libwebp/0008-sdl.patch

@@ -0,0 +1,36 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 7b0d2fa55..efd10887b 100644
+--- a/CMakeLists.txt	
++++ b/CMakeLists.txt
+@@ -563,10 +563,11 @@ if(WEBP_BUILD_EXTRAS)
+ endif()
+ 
+ if(WEBP_BUILD_WEBP_JS)
++  find_package(SDL REQUIRED)
+   # JavaScript version
+   add_executable(webp_js ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
+-  target_link_libraries(webp_js webpdecoder SDL)
+-  target_include_directories(webp_js PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
++  target_link_libraries(webp_js webpdecoder ${SDL_LIBRARY})
++  target_include_directories(webp_js PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${SDL_INCLUDE_DIR})
+   set(WEBP_HAVE_SDL 1)
+   set_target_properties(
+     webp_js
+@@ -578,14 +579,14 @@ if(WEBP_BUILD_WEBP_JS)
+ 
+   # WASM version
+   add_executable(webp_wasm ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
+-  target_link_libraries(webp_wasm webpdecoder SDL)
+-  target_include_directories(webp_wasm PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
++  target_link_libraries(webp_wasm webpdecoder ${SDL_LIBRARY})
++  target_include_directories(webp_wasm PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${SDL_INCLUDE_DIR})
+   set_target_properties(
+     webp_wasm
+     PROPERTIES LINK_FLAGS "-s WASM=1 \
+        -s EXPORTED_FUNCTIONS='[\"_WebpToSDL\"]' -s INVOKE_RUN=0 \
+        -s EXTRA_EXPORTED_RUNTIME_METHODS='[\"cwrap\"]'")
+-  target_compile_definitions(webp_wasm PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
++  target_compile_definitions(webp_wasm PUBLIC EMSCRIPTEN WEBP_HAVE_SDL WEBP_HAVE_JUST_SDL_H)
+ 
+   target_compile_definitions(webpdspdecode PUBLIC EMSCRIPTEN)
+ endif()

ports/libwebp/CONTROL

@@ -50,10 +50,6 @@ Description: Build the cwebp command line tool.
 Feature: dwebp
 Description: Build the dwebp command line tool.
 
-Feature: webp_js
-Description: Emscripten only build of webp.js. Deactivates all other options.
-Build-Depends: sdl1 (windows)
-
 Feature: swap16bitcsp
 Description: Enable byte swap for 16 bit colorspaces.
 

ports/libwebp/portfile.cmake

@@ -11,6 +11,7 @@ vcpkg_from_github(
     0004-add-missing-linked-library.patch
     0006-fix-dependecies-platform.patch
     0007-fix-arm-build.patch
+    0008-sdl.patch
 )
 
 vcpkg_check_features(OUT_FEATURE_OPTIONS FEATURE_OPTIONS