cmake: add messages about usages of vendored libraries

CMakeLists.txt

@@ -505,6 +505,7 @@ find_library(SDL2_LIBRARY SDL2)
 find_package_handle_standard_args(SDL2 DEFAULT_MSG SDL2_LIBRARY SDL2_INCLUDE_DIR)
 
 if(NOT SDL2_FOUND AND WIN32)
+	message(STATUS "Using vendored SDL2 library")
 	set(SDL2_FOUND TRUE)
 	set(SDL2_DIR "${SRC}/Windows/SDL2")
 	set(SDL2_INCLUDE_DIR "${SDL2_DIR}/include")
@@ -529,6 +530,7 @@ if(PROJECT_VKQUAKE)
 	find_package(Vulkan)
 
 	if(NOT Vulkan_FOUND AND WIN32)
+		message(STATUS "Using vendored Vulkan library")
 		set(Vulkan_FOUND TRUE)
 		set(VULKAN_DIR "${SRC}/Windows/misc")
 		set(Vulkan_INCLUDE_DIR "${VULKAN_DIR}/include")
@@ -649,6 +651,7 @@ function(FIND_CODEC)
 	find_package_handle_standard_args(${CODEC} DEFAULT_MSG ${CODEC}_LIBRARY ${CODEC}_INCLUDE_DIR)
 
 	if(NOT ${CODEC}_FOUND AND WIN32)
+		message(STATUS "Using vendored ${CODEC} library")
 		set(${CODEC}_FOUND TRUE)
 		set(CODECS_DIR "${SRC}/Windows/codecs")
 		set(${CODEC}_INCLUDE_DIR "${CODECS_DIR}/include")