fix extra dependencies and build errors

ports/libwebp/0001-build.patch

@@ -23,7 +23,7 @@ index 9503daacb..2fb9ef137 100644
  endif()
  
  if(WEBP_BUILD_GIF2WEBP)
-@@ -524,7 +528,10 @@ if(WEBP_BUILD_EXTRAS)
+@@ -524,7 +528,11 @@ if(WEBP_BUILD_EXTRAS)
  
    # webp_quality
    add_executable(webp_quality ${WEBP_QUALITY_SRCS} ${WEBP_EXTRAS_SRCS})
@@ -33,4 +33,5 @@ index 9503daacb..2fb9ef137 100644
 +  endif()
    target_include_directories(webp_quality
                               PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
++                                     ${CMAKE_CURRENT_SOURCE_DIR}/src
                                       ${CMAKE_CURRENT_BINARY_DIR})

ports/libwebp/0006-fix-dependecies-platform.patch

@@ -2,7 +2,7 @@ diff --git a/CMakeLists.txt b/CMakeLists.txt
 index 83edb3a..f634094 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
-@@ -540,7 +540,10 @@ if(WEBP_BUILD_EXTRAS)
+@@ -540,7 +540,11 @@ if(WEBP_BUILD_EXTRAS)
    find_package(SDL)
    if(SDL_FOUND)
      add_executable(vwebp_sdl ${VWEBP_SDL_SRCS})
@@ -11,6 +11,7 @@ index 83edb3a..f634094 100644
 +    if (MSVC)
 +        target_link_libraries(vwebp_sdl dxguid winmm)
 +    endif()
++    target_compile_definitions(vwebp_sdl PRIVATE WEBP_HAVE_JUST_SDL_H)
      target_include_directories(vwebp_sdl
                                 PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
                                         ${CMAKE_CURRENT_SOURCE_DIR}/src

ports/libwebp/CONTROL

@@ -33,7 +33,7 @@ Description: Build the webpmux command line tool.
 
 Feature: extras
 Description: Build extras.
-Build-Depends: sdl1 (windows)
+Build-Depends: sdl1 (windows), libwebp[vwebp]
 
 Feature: nearlossless
 Description: Enable near-lossless encoding