Zstd: Change package status to recommended

CMakeLists.txt

@@ -292,7 +292,7 @@ link_package(PNG TARGET PNG::PNG ENCOURAGED)
 link_package(ZLIB TARGET ZLIB::ZLIB ENCOURAGED)
 link_package(LIBLZMA TARGET LibLZMA::LibLZMA ENCOURAGED)
 link_package(LZO)
-link_package(ZSTD TARGET ZSTD::ZSTD ENCOURAGED)
+link_package(ZSTD TARGET ZSTD::ZSTD RECOMMENDED)
 
 if(NOT OPTION_DEDICATED)
     link_package(Fluidsynth)

cmake/LinkPackage.cmake

@@ -1,5 +1,5 @@
 function(link_package NAME)
-    cmake_parse_arguments(LP "ENCOURAGED" "TARGET" "" ${ARGN})
+    cmake_parse_arguments(LP "ENCOURAGED;RECOMMENDED" "TARGET" "" ${ARGN})
 
     if(${NAME}_FOUND)
         string(TOUPPER "${NAME}" UCNAME)
@@ -19,5 +19,7 @@ function(link_package NAME)
         endif()
     elseif(LP_ENCOURAGED)
         message(WARNING "${NAME} not found; compiling OpenTTD without ${NAME} is strongly disencouraged")
+    elseif(LP_RECOMMENDED)
+        message(WARNING "${NAME} not found; compiling OpenTTD without ${NAME} is not recommended")
     endif()
 endfunction()