cmake: make Vulkan-Headers external the default

CMakeLists.txt

@@ -37,6 +37,8 @@ option(ENABLE_WEB_SERVICE "Enable web services (telemetry, etc.)" ON)
 
 option(YUZU_USE_BUNDLED_FFMPEG "Download/Build bundled FFmpeg" "${WIN32}")
 
+option(YUZU_USE_EXTERNAL_VULKAN_HEADERS "Use Vulkan-Headers from externals" ON)
+
 option(YUZU_USE_QT_MULTIMEDIA "Use QtMultimedia for Camera" OFF)
 
 option(YUZU_USE_QT_WEB_ENGINE "Use QtWebEngine for web applet implementation" OFF)
@@ -211,10 +213,13 @@ find_package(inih)
 find_package(lz4 REQUIRED)
 find_package(nlohmann_json 3.8 REQUIRED)
 find_package(Opus 1.3)
-find_package(Vulkan 1.3.238)
 find_package(ZLIB 1.2 REQUIRED)
 find_package(zstd 1.5 REQUIRED)
 
+if (NOT YUZU_USE_EXTERNAL_VULKAN_HEADERS)
+    find_package(Vulkan 1.3.238)
+endif()
+
 if (ENABLE_LIBUSB)
     find_package(libusb 1.0.24)
 endif()

externals/CMakeLists.txt

@@ -152,6 +152,6 @@ if (YUZU_USE_BUNDLED_FFMPEG)
 endif()
 
 # Vulkan-Headers
-if (NOT TARGET Vulkan::Headers)
+if (YUZU_USE_EXTERNAL_VULKAN_HEADERS)
     add_subdirectory(Vulkan-Headers EXCLUDE_FROM_ALL)
 endif()