diff --git a/folly/portability/Time.h b/folly/portability/Time.h
index 264fbac4a8a..f51ff105b56 100644
--- a/folly/portability/Time.h
+++ b/folly/portability/Time.h
@@ -27,11 +27,7 @@
 // solve that by pretending we have it here in the header and
 // then enable our implementation on the source side so that
 // gets linked in instead.
-#if defined(__MACH__) &&                                               \
-        ((!defined(TARGET_OS_OSX) || TARGET_OS_OSX) &&                 \
-         (MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12)) || \
-    (defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE != 0 &&             \
-     (__IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_10_0))
+#if defined(__MACH__) && defined(__CLOCK_AVAILABILITY)
 
 #ifdef FOLLY_HAVE_CLOCK_GETTIME
 #undef FOLLY_HAVE_CLOCK_GETTIME