fix nonexistent vulkan-headers library

Author: YasInvolved

3rdparty/CMakeLists.txt

@@ -454,6 +454,11 @@ if (NBL_BUILD_BULLET)
 	set(BULLET_INCLUDE_PATH ${BULLET_INCLUDE_PATH} PARENT_SCOPE)
 endif()
 
+if (NOT TARGET Vulkan::Headers)
+	add_library(Vulkan-Headers INTERFACE)
+	add_library(Vulkan::Headers ALIAS Vulkan-Headers)
+endif()
+
 target_include_directories(Vulkan::Headers INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}/Vulkan-Headers/include")
 add_subdirectory(Vulkan-Tools/vulkaninfo vulkaninfo EXCLUDE_FROM_ALL)