--- CMakeLists.txt	2026-07-15 01:41:06.000000000 +0800
+++ CMakeLists.txt	2026-07-20 03:42:25.000000000 +0800
@@ -88,46 +88,7 @@
     list(APPEND EVENT_LOOP_DEFINES "EPOLL")
     set(USE_S2N ON)
 
-elseif (APPLE)
-
-    file(GLOB AWS_IO_OS_HEADERS
-            )
-
-    file(GLOB AWS_IO_OS_SRC
-            "source/bsd/*.c"
-            "source/posix/*.c"
-            "source/darwin/*.c"
-            )
-
-    find_library(SECURITY_LIB Security)
-    find_library(NETWORK_LIB Network)
-
-    # Enable dispatch queue if the libraries are available
-    if (NETWORK_LIB AND SECURITY_LIB)
-        list(APPEND PLATFORM_LIBS "-framework Security -framework Network")
-        list(APPEND EVENT_LOOP_DEFINES "DISPATCH_QUEUE")
-    endif ()
-
-    # Enable KQUEUE on MacOS only if AWS_USE_SECITEM is not declared. SecItem requires Dispatch Queue.
-    if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin" AND NOT DEFINED AWS_USE_SECITEM)
-        list(APPEND EVENT_LOOP_DEFINES "KQUEUE")
-    endif()
-
-    # On MacOS s2n-tls is optional (the Apple SecItem/Security framework provides a TLS implementation).
-    # Default to using s2n-tls only when SecItem is not requested. Users can override with -DUSE_S2N=ON/OFF.
-    if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin" AND NOT DEFINED AWS_USE_SECITEM)
-        option(USE_S2N "Use s2n-tls as the TLS implementation." ON)
-    else()
-        option(USE_S2N "Use s2n-tls as the TLS implementation." OFF)
-    endif()
-
-    # Force USE_S2N OFF to avoid pulling in an unused s2n dependency.
-    if (DEFINED AWS_USE_SECITEM AND USE_S2N)
-        message(WARNING "AWS_USE_SECITEM takes precedence over s2n-tls; forcing USE_S2N=OFF to avoid linking unused s2n.")
-        set(USE_S2N OFF CACHE BOOL "Use s2n-tls as the TLS implementation." FORCE)
-    endif()
-
-elseif (CMAKE_SYSTEM_NAME STREQUAL "FreeBSD" OR CMAKE_SYSTEM_NAME STREQUAL "NetBSD" OR CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
+elseif (APPLE OR CMAKE_SYSTEM_NAME STREQUAL "FreeBSD" OR CMAKE_SYSTEM_NAME STREQUAL "NetBSD" OR CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
     file(GLOB AWS_IO_OS_HEADERS
             )
 
@@ -138,6 +99,7 @@
 
     list(APPEND EVENT_LOOP_DEFINES "KQUEUE")
     set(USE_S2N ON)
+    add_definitions(-DAWS_APPLE_USE_S2N_ONLY)
 
 endif()