fix: suppress libffi cmake warnings

CMakeLists.txt

@@ -13,12 +13,21 @@ endif()
 include_directories(include)
 include(FetchContent)
 
+# --- libffi ---
+
+set(PREV_SUPPRESS_DEV ${CMAKE_SUPPRESS_DEVELOPER_WARNINGS})
+set(CMAKE_SUPPRESS_DEVELOPER_WARNINGS TRUE CACHE INTERNAL "")
+
 FetchContent_Declare(ffi
 	GIT_REPOSITORY "https://git.samsonium.dev/samsonium/libffi.git"
 	GIT_TAG "main"
 )
 FetchContent_MakeAvailable(ffi)
 
+set(CMAKE_SUPPRESS_DEVELOPER_WARNINGS ${PREV_SUPPRESS_DEV} CACHE INTERNAL "")
+
+# --------------
+
 # Compiler
 add_executable(fzc
 	src/compiler/utils/fzl_const_pool.c