From https://github.com/winterheart/aseprite/tree/v1.3.16.1-unbundle
From: "Azamat H. Hackimov" <azamat.hackimov@gmail.com>
Date: Sun, 10 Jul 2022 20:14:00 +0300
Subject: [PATCH 3/7] Use shared webp library

Added option -DUSE_SHARED_WEBP
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -74,6 +74,7 @@ option(USE_SHARED_LIBPNG  "Use your installed copy of libpng" off)
 option(USE_SHARED_TINYEXIF "Use your installed copy of TinyEXIF" off)
 option(USE_SHARED_TINYXML "Use your installed copy of tinyxml" off)
 option(USE_SHARED_PIXMAN  "Use your installed copy of pixman" off)
+option(USE_SHARED_WEBP    "Use your installed copy of webp" off)
 option(USE_SHARED_FREETYPE "Use shared FreeType library" off)
 option(USE_SHARED_HARFBUZZ "Use shared HarfBuzz library" off)
 option(ENABLE_ASEPRITE_EXE "Compile main Aseprite executable" on)
@@ -383,21 +384,27 @@ add_subdirectory(laf)
 
 # libwebp
 if(ENABLE_WEBP)
-  # Use libwebp from Skia
-  if(LAF_BACKEND STREQUAL "skia")
-    find_library(WEBP_LIBRARIES webp
-      NAMES libwebp # required for Windows
-      PATHS "${SKIA_LIBRARY_DIR}" NO_DEFAULT_PATH)
-    set(WEBP_INCLUDE_DIR "${SKIA_DIR}/third_party/externals/libwebp/src")
-    if(WEBP_LIBRARIES)
-      set(WEBP_FOUND ON)
+  if(USE_SHARED_WEBP)
+    find_package(PkgConfig QUIET)
+    pkg_check_modules(WEBP libwebp libwebpdemux libwebpmux)
+    include_directories(${WEBP_INCLUDE_DIR})
+  else()
+    # Use libwebp from Skia
+    if(LAF_BACKEND STREQUAL "skia")
+      find_library(WEBP_LIBRARIES webp
+        NAMES libwebp # required for Windows
+        PATHS "${SKIA_LIBRARY_DIR}" NO_DEFAULT_PATH)
+      set(WEBP_INCLUDE_DIR "${SKIA_DIR}/third_party/externals/libwebp/src")
+      if(WEBP_LIBRARIES)
+        set(WEBP_FOUND ON)
+      else()
+        set(WEBP_FOUND OFF)
+      endif()
     else()
-      set(WEBP_FOUND OFF)
+      set(WEBP_FOUND ON)
+      set(WEBP_LIBRARIES webp webpdemux libwebpmux)
+      set(WEBP_INCLUDE_DIR ${LIBWEBP_DIR}/src)
     endif()
-  else()
-    set(WEBP_FOUND ON)
-    set(WEBP_LIBRARIES webp webpdemux libwebpmux)
-    set(WEBP_INCLUDE_DIR ${LIBWEBP_DIR}/src)
   endif()
 endif()
 
--- a/third_party/CMakeLists.txt
+++ b/third_party/CMakeLists.txt
@@ -31,7 +31,7 @@ if(NOT USE_SHARED_GIFLIB)
   add_subdirectory(giflib)
 endif()
 
-if(ENABLE_WEBP AND NOT LAF_BACKEND STREQUAL "skia")
+if(ENABLE_WEBP AND NOT USE_SHARED_WEBP AND NOT LAF_BACKEND STREQUAL "skia")
   set(WEBP_BUILD_EXTRAS OFF CACHE BOOL "Build extras.")
   set(WEBP_BUILD_ANIM_UTILS OFF CACHE BOOL "Build animation utilities.")
   set(WEBP_BUILD_CWEBP OFF CACHE BOOL "Build the cwebp command line tool.")
-- 
2.51.2